Like most mountain bike setups, I have a single chainring. I started with a 34-tooth chainring and 11-speed drivetrain. As I rode further up into the Sierra Nevadas on my scouting rides, I found I wanted a lower gear. My choices were (1) upgrade to a 12-speed, or (2) get a smaller chainring. Much cheaper to replace the ring. Also, the only thing I lose by not going 12-speed is a higher gear. And the last thing I’m worried about is going faster than I can pedal. Plus, a 12-speed chain is thinner and more fragile. So now I’ve got a 28-tooth chainring, which if I recall correctly, is the size of the largest cog on my old road bike.
I don’t know that I can climb anything steeper, but the lower gearing allows me to get up those steeper sections more easily and not wear my knees out doing it. I silently thank Rick every time I drop into first . . . which, at a top speed of about 4 mph, is a lot of time to give thanks.