I leave the halter on with a lead rope attached if it has a purpose. For example if I'll be out on the trail for hours and might want to get off the horseback and walk for a while to stretch my legs, or sometimes I cross areas where it's too dangerous to be mounted, boggy areas or scree areas, then I want to get off and lead the horse by a leadrope and not by the reins. If I loose my balance walking in such areas I might jerk the horses mouth if leading by the reins and I don't want to cause the horse pain. It's also handy to be able to tie the horse safely if you let him wear a halter and a lead rope.
Don't fence me in