Although drywall removal doesn't cost a fortune, what's the point of going through all this trouble when you can prevent some home problems? Apart from aesthetic or practical purposes, drywalls or parts of them would have to be removed when they are contaminated with mold. Though, this is not the only enemy of your drywalls. If you redecorate your house often, you will find that there are too many nail holes behind the pictures on your wall. Eventually, you might even discover defects and there will be some corners on the ceiling that won't be flat.
Some problems are prevented and some are fixed. For example, proper drywall installation ensures that you won't see spots, which are not flat. This might be caused by wall studs, which may dry out. Of course, you can hardly predict that water pipes will break and damage the drywall. Such problems can be partially prevented by checking the plumbing system often. On the other hand, who does that? And who is to say that if the pipes are fine today, they will be fine tomorrow?
It's better to stick to things you can control. Your goal should be to avoid major problems. If you have furniture covering your drywalls, push them over every once in a while to make sure the drywalls are clean and not damp. If you see wet areas and, most importantly, if you discover mold, make sure the area is treated properly and fast. Make sure the area is dried before you use textured paint to cover the stain. When drywalls are coated, they are cleaned easier, too. Baking soda is the best solution for mold but also for cleaning walls and will have no effects on your respiratory system.
Don't make too many holes in the drywall unless you are absolutely sure where you want to hang your pictures. Even if you have opened way too many holes, cover them. Spackling is your solution. This material will close small holes and cracks. If the damage is bigger, you will need more effective solutions. Big holes will need patching. Mold on unpainted drywalls won't be removed. Drywalls are porous and you will be urged to cut the contaminated part of the drywall and have it replaced. Make sure the new part is properly installed, the perimeter joint sections are covered with compound to seal the cracks, the area is sanded when dried and the area is painted with a matching texture coating of your walls.