I use it literally everywhere out of habit, I got made fun of for using it when pulling out of my moms driveway once lol
The only reason I won't possibly use it is when I'm in a turn only lane at a red light and don't want to listen to it for 3 minutes
Most people I find only use it 75% of the time at best.
I'm 2.5 years into driving and am curious if it's just what semi-new drivers do or if I'm the odd one out.
Yes. You're supposed to use it anytime you're about to turn or change lanes, including if you're sitting in a turn lane at a red light or backing out of a drive way or parking spot.