I don't see the need for the kind of repetition that Dan seems to advocate. Once a piece is polished enough to perform, and has been incorporated into the performance repertoire there is little to be gained from further rehearsal--If pieces are not working out in performance, and require continuous attention then it is wise to consider shelving it in favor of something more suited to the emsemble's range--

The abilities of the leader/director are the most important element in a non-professional group, because through choice of material,arrangement and proper management of rehearsal time, they determine how far you get, and how soon you get there--