I go one season without freshing it up, of course I check up on things pretty good. Spring pressure and valve lash is a every couple weekend thing. One season for me is normally anywhere from 200-300 passes, I've done this on my SBC and BBC's and only had one issue (comp roller lifter break)
I see a lot of people going well over 300-400 passes without anything but springs also, even see some take the intake off stick lifters in it and just keep racing them.