I only cut split ends (I only got them twice in 1 year thanks to clay treatments and protein overload). No problem at all. 1 dusting and 1 search and destroy in 1 year and my hair is perfect condition: no need to trim all the time.
I find that I got the most ssk when I was shoulder length, but then again, after that I started wearing braidouts, moisturizing daily and using ceramide oils. Before that, I used to co-wash and wear wash and go's with gel everyday, and I had almost 1 knot per strand, so maybe it was the different routine and the hair constantly touching my shoulders.