In the past, I would typically carry on for solo trips, but check for trips with the rest of my family. My thinking was that I'm perfectly fine navigating the airport with a bag, but when I have to corral my family, I'd rather have one less thing to worry about.
Recently, I've started checking more often, unless I'm just doing a few nights and can fit in my small soft-sided bag. I'd rather not deal with the "fight for overhead space" game. Instead of trying to jockey onto the plane early within my boarding zone, I can spend a little extra time in the SkyClub, and just wander on 25 minutes before takeoff. What's more, now that fewer people are checking luggage, my bags seem to be on the carousel within just a few minutes of my arrival in baggage claim----and half the time, they are already there---so there isn't the delay there once was.
It helps that my Delta AmEx gives me one free bag per person, but even without that, well, you can spend money for convenience, or you can spend effort to avoid spending money. Where you fall on that question really depends on your tolerance for inconvenience and how much the bag fees hurt. When I'm on vacation, I have a *very* low tolerance for inconvenience. I'll regain status on my next flight (I lost it last year), and with early boarding might go back to carrying on for solo trips.