My old helper asked why I still stretch by hand on stairs, and his reason made me switch
Last Tuesday my old helper Marcus came by a job in Fresno to pick up a check and watched me pull a stair run with a knee kicker like I have for 15 years. He said his new crew uses a power stretcher on stairs with a stair tool and it saves his knees, and he is only 26 with no pain yet. I brushed it off until I did a 14 step run the next day and my left knee was barking at me by step 9. He was not wrong, the power stretcher got it tighter on the nose too. Anybody else made the switch on stairs or am I about to be the old guy with bad knees making excuses?
So what happens when that power stretcher slips on a stair and tears the carpet off the tack strip? With a knee kicker you feel every inch as you go, so you know right away if the backing is weak or the pad is bunched. A power stretcher just keeps cranking and hides the problem until it rips, and now you are redoing a whole run for free. On stairs you are working tight and weird, not some open room where you can see everything. Marcus is 26 and his knees are fine because he has not put in the years yet, but give him 15 more and see if he still loves that machine. A knee kicker is not just about your knees, it is about control.
The "power stretcher just keeps cranking and hides the problem" part is exactly what worries me. I watched a guy on a hotel job last year stretch a landing with a power unit and he never felt the backing let go until the whole nose popped off the tackless, cost him half a day to redo. With a kicker you feel that little give in your foot and you stop, back up, fix the pad. My knees are already shot at 44, but I will take sore knees over ripping out a finished run for free.