OOOOh! Yuck! I do encourage a ton of independence, but I will usually wipe until they are just about ready for school, preschool or kindergarten. (where they need to do it on their own) I dont like the thought of poop on stuff or in my home. They know when they have to poop, they need to inform me, they go by themselves and yell "I'm done!" when they need a wipe. Besides that, if I let them wipe alone, ewe! poop on the seat, their hand, and half a role in the toilet. No thanks. not to mention, when they are little they dont wipe well, who would want a sore butt?
I also use wipes and throw in trash, that way I know they get wiped well.