There is a limit...BUT...every person has a different limit.
My limit is probably somewhere around 2 feet long. I’ve never tried to find my limit. But there was a few years way back in a galaxy far away, where I tried for long hair and I couldn’t even get my hair to fully cover the back of my collar.
My sister, on the other hand, could grow hair long enough to sit on...EASILY. She even had her hair trimmed regularly and it still kept getting longer.
daily doses of Folic Acid -800mcg help, too but there is also the culture of selling hair in 3rd world countries
I had my hair finger-tip length for a while - had to keep it in a French braid all the time, or it would catch on things; I’d shut in the door behind me; it would tangle in about two minutes. Too fine and heavy to put up, so I was limited to that rope of hair hanging down in back, no variety for all the time it took to brush and braid. I’m not growing it long again.