I think the hardest thing for newbies to learn is how not to bring things. You don't need every little gadget that REI sells. You don't need a change of clothes every day. You don't need the expedition first aid kit with every thing under the sun that you don't know how to use. We tend to pack our fears and newbies have more fears.

The reason I bring this up in this thread is because if you pack your wife's things in your pack it frees her up to pack more extraneous things. If she packs the essentials (like Daisy recommended) she will have less room to pack things she doesn't need.