You have to tune yourself in to be able to recognise the point of diminishing returns, I find:
"Well the music is all perfect but the production could be improved. But that would mean replacing all the drum samples with higher-quality ones, which would mean re-EQing them and fine-tuning the effects again. But then that would mean the bassline would no longer match the percussion, so I'd have to use a different patch or even a different synth - and I bounced it down ages ago but I'm sure I've still got the MIDI in one of the project backups... hm... which one though... fuck it, I'll leave it".