Even if it means just being smart enough to know when to quit.
Example: Moving a piano.
When the right equipment is used and the piano is properly prepared for the move, two (reasonably healthy) guys are all that’s needed, but heaven help folks trying to move a piano w/o the proper equipment and mental “muscle,” because physics surely will not. My last “piano move” 20 years ago: good equipment, me, a 12-y.o. boy and a 14-y.o. girl (both a couple of standard deviations above the mean and able to take direction very well). Moved the piano out and loaded into truck. Arrival at destination? It took me and three inexperienced guys who apparently were not as bright as my two kids to move it in and set it up. ‘S’truth.
Nowadays, I’m smart enough to know that–at my age and physical condition–hiring someone would be better, because despite knowing how to move one, I’m just getting to be too old for the gig. *sigh*