My fleet spends a relatively lot of time in the non-towered environment. Fortunately, my previous lives had a super solid background in non-towered and non-radar environments, and my personal flying has kept me up to speed as well.
You HAVE to bring your "A" game, which can be a challenge at 0500. What is an easy departure at noon with the tower open becomes an unwieldy mess at 0500 with de-icing, plowing, random NOTAMs, getting clearances/releases from the RCO, etc. And that's assuming no other traffic. Not only are there plenty of challenges, but it really can get you out of your groove.
121 adds whole layers of additional drama. What would have been no big deal in a Bonanza turns into a complicated mess 121. You have to slow down, check the boxes, have both people in the loop and paying attention. If your partner isn't super up to date on non-tower ops, you need to slow to a crawl and make sure they're with the program.