In my playing, there are always those couple tension rods that will come loose under regular playing. When they come loose, I just tighten them back up, but if that doesn't sound right, I'll tune the drum. Otherwise, I tune before each gig, which for me can be anywhere from once every few days to once every month depending on the current schedule.
Ever since I got a Tune Bot, drum tuning has been an absolute breeze, so it takes almost no time to check over the tuning and fix it before I put the drum in the bag when I'm packing up for a gig.