I Captain and have for a few years. I play/captain 4.0 and play up to 4.5 level.
If my team is deeply talented and players are readily available I play "straight up" all season. If my team is not deep but I have a few very strong players I mix up my line ups all year long (mostly randomly) so there isn't a pattern to exploit. This is common from local league all the way through states and sectionals from my experience.
Thankfully, Jay, TopDawg, CDNdude are there to back up my occasional fart! -Kish