I always get a hydration bladder pocket in my packs, all of them - I never use water bottles. I've had them leak, break, and generally I won't drink enough water if I don't have a bite valve in front of me all the time.

I put everything in the pack itself and never in side mesh pockets where they can be ripped out of the pack by a bush or fall out when I drop the pack. (But I am not always on a nice brush-free trail.)

I never put anything in a front pocket for the same reason.

Everything depends on where and when you go.