Back when mine was really long I used to have to take an inch or so off every now and then or it would just sort of stop growing and the ends would frizz. Nothing I tried ever really worked once the damage was done.
Once upon a time it was below my waist.
Now I'll let it go to about the center of my back and then cut it back to below my shoulders in the summer.
I never blow dry it. For me, that's the worse thing ever. Condition, wrap in towel and dry seems to work the best. I have fine hair, but a lot of it thankfully.