I routinely (well, ever so often) use Jaikoz to go over my library and improve tags. What happens is that it queries Discog for 5 000 songs and then gets blocked for a day. When I run it later on it appears to run over the songs in the same order, and only query the same 5 000 songs.
Iff that actually is case: I would like is that Jaikoz keeps track of songs it has queried and skips them the next time (unless there is still room in the 5 000 queries quota). Maybe in an LRU fashion. This would mean all songs get the Discog treatment once in a while.