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.