Grow where it’s hard enough to stretch you but not so hard it scares you into quitting. Find that line.

Growth needs resistance at a specific weight. Too little and nothing adapts. Too much and you flinch away from the whole enterprise and do not come back, which costs far more than a gentler pace would have. The useful zone is uncomfortable but not frightening, and it moves as you do.

Check where your current challenge sits. If you are bored, add something. If you are dreading it to the point of avoidance, make it smaller until you can approach it. Difficulty is a dial, not a test of character.