So I just hit 500 planets. With the exception of a few core planets I simply can't keep track of all of them, which has resulted in a good deal of them being rather screwed over. My favorite mistake was planets that have hit 75 society level, but have rubbish population. Must have used those ones for arc-jumps early on.
I think I need to work on some scripts to help monitor and organised my planets, and I certainly have some new ideas how to start out if there is another reset.