I have not been backpacking too much but I am trying to plan some trips. Is it best to buy a guide book and travel according to it, or is a trip more fun if you just play it by ear and figure out things as you go?

Books are great for ideas and to get a 'lay of the area'. They are worth having just for that - and for help on water, campsites, etc.
You don't need to carry them with you (make notes on your maps!).

I find the guidebook useful when I haven't been hiking in an area before. For a beginning hiker, then, I would recommend using a guidebook to plan trips.

I also agree. A guidebook can be quite useful for planning. I would never take one on a trip, though I have copied or scanned a few notes on occasion. Do remember, though, that the trips listed in the guidebooks will have more people on them.

The other useful planning tool is the larger scale Forest Service maps of wilderness areas. For example, I found the USFS Bridger Wilderness map a far better planning tool for the west side of Wyoming's Wind River range than the Earthwalk Press maps. The latter don't have nearly as much detail and are also heavy and bulky. However, I've stopped taking the whole map anyway and instead scan and print out the portions I'll need, and only if I need a supplement to topographic maps. I've been known to cut maps up, too.

I have planned plenty of trips using only USFS and topographic maps. I wouldn't do this until you've had more experience in that particular region, though.

The other thing to remember is often a guidebook is not a substitute for a decent topo map. While you may be fine on popular maintained trails - if the guidebook is talking about trips well off the beaten path, the book can sometimes be a bit out of date - particularly if you're looking at a trip the author might have done 15 years ago.

That doesn't mean "ignore a guidebook" - they're very useful.. I just typically wouldn't rely on one for routefinding.

Phat is correct--a guide book is a supplement, not a substitute, for a good topographic map (and knowledge of how to use it). It is a planning tool, not a navigation tool. A very few guidebooks have topo maps in them, which you could copy and enlarge, but most have just sketch maps which aren't good for much.

The same is true for the larger scale USFS maps, except that those are better for pre-trip planning in that you can spot loop trails and such.

Most guidebooks are for day hiking and very few will have multi-day backpacks listed. You may have to plan your trip first and then read the guidebook entries for the individual trails.

If you are new to backpacking which it sounds like you are from your opening, guidebooks are great, use them in conjunction with a basic topo map and stay on the more popular trails until you get use to route finding using a guidebook and work on some map reading skills while in places where it is hard to get lost. There are plenty of guidebooks with multiday trips and they normally mention ranger and forest service info that you can call and ask ? and get maps. As you get more experienced you can venture out further and make your own trips using maps alone.

Just echoing the former posts, and adding that many guidebooks drop little nuggets of information that can catch your eye, and make you wonder about a specific area, and that interest will draw you in and make your search and trip planning that much more interesting and exciting.
I also like to search online for "trip reports" and read first hand what others have done, and where they have gone and what they have experienced on their trips. Just do a google search of the area in question, with the words "trip report" after it and you will be amazed at how many folks write up their trips.
Enjoy the learning and planning stages, as its a part of your trip as well. I love the hours I spend poring over maps and ferreting out obscure info about areas I hope to go hike in. It all adds to the flavor of my trip.

One last thing about guidebooks - newest is not always bestest either.

Out here in the PNW for example backpacking guide books have fallen to the side as day hiking books took over in the past 8 or so years. But also trails have slowly disappeared, often by quiet request of the NF, NP or whoever is in charge of the area. They have effectively shunted people to a set of main trails. This isn't bad overall for the area - it gives it a rest. But....if you want to know about hidden areas, go buy those old books and read. Get maps. Search. But don't waste your time asking rangers, they will often lie to your face to keep people away. If you have a local hiking forum (we do here) ask away.

What?? Rangers lie?? Shocking!! Actually, it as likely that they were just hired five minutes ago and have no first hand knowledge of the trails. Anyone can wear a uniform....

Once in a while you will still encounter one with useful info. They haven't all retired yet..

Here in NW Oregon, there's a brisk trade in used book stores for the trail guides by Don and Roberta Lowe, most of which were published in the 1980's. They're a wonderful guide to "lost trails." I moved here in 1989 and bought a whole bunch of them. I also hiked some of the trails before they disappeared altogether.

While it's a good idea to contact the appropriate ranger station to find out about local conditions, you may or may not learn much. Some forest service staff get out and really keep track about what's going on. Others seem to get no farther than the front door of the ranger station on the way in and out. I remember the time I called to ask if a trail were snow-free. I was told it was still under snow. When I got out there, I found no snow anywhere near the place. Either nobody had been there for 4 weeks or somebody drove by the trailhead really fast and mistook massive beds of trilliums for snow!

Last fall, I tried to find some information about the Wallowas. I was told by the USFS that the trail I wanted to take was not passable because the bridge was out and the trail was no longer being maintained. I didn't believe that one because said trail is one of the most heavily used trails in the whole range! I found out from a local forum that the trail was in perfectly good condition, that there was a nice wide log across the creek and that the creek is also quite fordable in low water.

On the other hand, summer before last I visited the Lander, WY ranger station on my way to a backpack in the Wind Rivers. My hike was on the other side of the mountains, in a different national forest. The woman at the desk not only had the exact information I needed but also called the other national forest on the other side of the mountains to confirm it!

Forest Service websites are often not up-to-date and should not be relied on. On the other hand, local forums, such as portlandhikers.org in NW Oregon/SW Washington and nwhikers.net in the Seattle area, are excellent sources of information.

Yep, like Granny I rely on actual hikers for up to date info. Sadly so does our NF offices around here as well! They don't send rangers out often to do trail conditions so if you want the scoop out here you visit the two local forums (Portland Hikers and NWHikers (for Washington) and as well the WTA (Wa Trails Association) for the latest scoop. Often in prime season you can get updates from a day or two before that is unbiased.

Last summer there was a real bone of contention with the FS here - part of the PCT was closed due to a fire. So the FS came up with a pretty lame detour. Yet you could do a way better detour using the old Cascade Crest Trail - all on trails well maintained. Yet the FS office at Snoqualmie Pass was refusing to sell a complete set of topo maps to thru hikers - they would not sell the one map needed to see the route. I heard those ladies with my own ears telling the thrus "they had to take the official detour". By what order? They didn't like it when I questioned that.

An hour later I held court at the Pancake House and showed every thru there how to take the BETTER detour that was perfectly safe and didn't involve god awful road walking in Eastern Washington......

Guidebooks are great, just take the information with a grain of salt. Some are way too conservative - say it will take 5 days to get somewhere that 3 will do. Others are "sandbagged" - most often those written by climbers. The Sierra High Route is a great read - but sandbagged. Arnot's Sierra- Range of Light is fantastic for pointing you to wonderful areas - but way too conservative on travel times. And really be wary of internet trip reports. Hikers who push it 20+ miles a day like to beat their chests on the internet.

USGS 7.5 minute maps the gold standard. Draw your route, figure mileage and elevation gain. Then estimate about 1.5 mph on trail (for a beginner) and add one hour for each 1000 feet elevation gain and you get a ball-park idea of the time it will take. Off trail - it is 1 mph or less.

Then again - if you are specifically out to have a true "exploration experience" go with the maps and do not read the guidebooks. I do not recommend this for beginners, however. After some experience, this is OK.

Roald Amundsen, who led the first successful expedition to the South Pole, put it best:
"Adventure is just bad planning."

Take a course or go with experienced hikers until you actually know something and don't just wander off thinking you can make things up as you do along and come home safely. It doesn't always work out that way.

I have brought this up before and will do it again. Backpacking is a great activity, but like most things it requires certain skills. You don't just buy a bunch of gear and instantly know how to use it or understand what can happen to you if you aren't careful. That isn't how it works.

I have read a lot of accident reports and often inexperience is a major factor that results in injury or death. Sometimes people just disappear. Happens every year. The bottom line is be sensible. Backpacking is more than just a walk in the park with a pack on.

Tom is so right--there are a lot of skills connected with backpacking that you need to learn. One of them is regulating your body temperature so that you don't sweat while hiking but don't get chilled, either. This particular skill can be practiced around home in winter weather, and uses what I call the "onion principle"--putting on and taking off a number of thin layers. Another skill is pitching camp and breaking camp without letting your critical insulating items (clothing and sleeping bag) get wet. Backyard camping and overnight camping close to your car are good ways to practice various skills. And do find more experienced people to go with. Googling "hiking clubs" for your area is a good way to find such people. I would expect that you shouldn't have problems finding such things in Germany!

Wandering_Daisy is correct, too, in that you have to watch out for the agendas of the folks writing guidebooks. I'm at the very slow end of the spectrum (1 mile per hour or less unless the trail is really smooth and level), so I really have to be careful.

It is surprising how many personnel in both the NPS and USFS just plain do not get out.

I remember one trip in the Grand Canyon, actually a caving trip, where we were obtaining our off trail permit for Tapeats Cavern. It was my first trip in that area, but I was with some very experienced cavers,most of whom had been in Tapeats at least once. It became painfully obvious during the course of the conversation that the ranger in charge of granting the permit did not have the vaguest idea of what was involved in a trip into the cave...

In a perfect world, a newly assigned ranger would spend her first two weeks (at least) walking the trails and learning the area, only then reporting for some useful work.

Robert Falcon Scott, who led the second expedition to the South Pole, had an adventure....

An extreme example, but Scott's fate should be a good warning that even with planning, things can go wrong. Scott thought ponies were a good mode of transport and that turned out not to be the case. (For those who might not know the story, Amundsen beat Scott to the South Pole and returned home safely; Scott and his men got to the pole, but froze to death on the way back.)

Wikipedia has a good article on Scott which shows that even with planning, things can go wrong. Scott made some bad decisions, had some bad luck and paid the price for it. You may never find yourself in Scott's position, but bad things can happen, even in your local mountains. Planning may not eliminate all the risks, but it surely will minimize them.

I have always admired Scott's nearly final words in his journal which are, more or less, "We took chances. We knew we took them. Things have come out against us. Therefore, we have no cause for regret."

Its a bit comical, as both Wandering Daisy, who has a guidebook in the writing stages, and myself, who has already published one; we both start out with so much information, and then we try to get it into a usable format. The sheer volume of subjective data leaves me shaking my head! Its true, each individual who used the info will use it differently. No matter how you present it, its either too much, not enough, right, wrong, or indifferent!
So like Daisy said, take it with a grain of salt and use all the info to build up your own data base so that when you finally have to make a decision, you can give it your best shot when you decide how and where to go.
A really good climber used to say, "its fun, its just a different kind of fun..."

I might also mention that you need to leave a detailed itinerary with someone who knows to call and where, if you aren't in contact with them by a certain time, in case you get lost or hurt and need help. So you do need to plan. Playing it by ear in small ways is okay... day hiking to one lake instead of another, or camping a mile further up the trail than expected, all good - as long as someone knows what trail you went in and will come out on, how long you expect to be there, and has a good description of you. Can't expect the cell phone or the PLB or the weather to cooperate one hundred percent of the time.

Really, odds are pretty good that you'll be okay... but we can't take that for granted. Use the guide books and talk to other hikers, and go with them if you can - I started out solo and don't recommend it, you learn more and faster when you are with people who've done it a lot.

Try to remember that a guide book is just that -- a guide. Nothing trumps real experience. Even when hiking into a new area (I did the High Uintas for the first time this year), I'll often read guide the book and then do a trip not even listed. Trust your maps.

I forgot to mention another reason for guidebooks - great to own for bedside reading! I have a large library of guidebooks, some to areas I have never gone too, but on rainy winter nights, I love to read and re-read the guidebooks. I sort of "do" the trips in my mind. I find this more enjoyable than reading fiction. And it really does not matter to me if I ever go to all the places.