I try to do carry-on only as it does help me to not over-pack and saves a few bucks in the process. Yes, sometimes difficult decisions need to be made on what to leave behind.
Most of the times that I have gone carry-on only I ended up checking my bag at the gate anyway at no charge. Airline employees at gate seem to always be requesting that on my flights. As more and more people do carry-on only, the overhead bins fill up faster and they run out of space. So they ask people to gate check. I pull out my tablet and anything else I want on the flight and go ahead and check it. Especially if my wife has already checked a bag (and seemingly almost every pair of shoes she has purchased over the last 23 years...but I get it...a woman has to accessorize!!!)