I did mean every month, perhaps less frequently. Basically, if the piece is just way ahead of where you are now, something you really should not be playing yet, practice a few easier bars, then as you learn and master easier pieces, you map new techniques you pick up onto the previously difficult "dream piece". It is quite a motivator to be able to play a couple of bars of "the dream". I think this helps a little sight reading too, because you are almost starting from scratch each time, but you have that motivation driving you on.