I've done a lot of research on this topic on blogs, here on the forum, from quilt shop owners and even one fabric manufacturer. The best advice I'd give is for you to prewash your fabrics to get out any chemicals that might be used for sizing, dying, etc. Most fabrics these days don't run, but some do, especially dark batiks, so that's another good reason to prewash. I wash mine as soon as they come through the door so that I know everything I have has been prewashed. Except for precuts. Too tough to wash those! If you like the crisp feel of unwashed fabric, I recommend Mary Ellen's Best Press. It works great.

I didn't used to wash my quilts after quilting them but now I do after hearing many good reasons here on the forum. I have cats, so that's one good reason to wash them. They can also become dusty from being out and about. Plus, we have oil on our hands that will get on the quilt. And you do get that lovely crinkly look to them after washing and drying! I love that. And you will see if there are any problems with seams holding up. You'd hate to give away a quilt that is coming apart in one or two places. I partially dry mine in the dryer, then hang outside on a chair (no clothesline) to finish drying, but I don't see any reason why it can't completely dry in the dryer. Once it's given away it will probably go through the washer and dryer many times, especially if it's a quilt for a child.

Wallhangings? I never wash those because I want the crisp, flat look. I use the flattest batting I can find and even iron the top when it's done. They hang better that way, nice and flat and straight. I don't want the puffy, crinkly look on them so I do not wash them. I occasionally clean them with a lint roller to keep them free from dust. (Can you tell I live in an old house?)

I'm sure you'll find different opinions to answer your question. Weigh the pros and cons and decide for yourself which method is right for each of your individual quilts. And have fun quilting!