That's probably what's causing it to not grow: I do not cut the tips.
Pro-tip from someone whose hair is below their bum & hasn't had a haircut in almost 2 years-keep it in a low, semi-loose bun. It helps to protect the hair from the elements/basic exposure, so less splitting, less breakage, MOAR HAIR! Also, always wash & rinse your tresses in cold water. Not icy of course, but as cold as you can take it is good; makes it shinier & softer by helping to smooth the cuticle. I also always use a square paddle brush & start at the ends of my hair when brushing & slowly working my way up. Gets rid of tangles with minimal stress/damage to the hair.
I'll post pics of my mane soon, just been feeling not so good about my weight & stupid bastard faced rosacea, but whatevs, it's not a beauty contest here...though there are a lot of pissing contests.