You waited 6 months to get a trim because you are growing your hair, every time you get it cut they cut too much off so whats the point right?
Well if each time you go and get your hair cut, if too much is being cut off then it means your going to the wrong salon. You have to balance your hair goal to the hair condition and leaving it for 6 months means you will possibly have more split ends than what you will cut off. To maintain a shape or condition your hair needs trimming every 6-8 weeks maximum. You remove split ends, keeps the shape right and keeps you looking sorted. If you don’t get it cut then the split ends travel up the hair shaft and the condition goes for a toss.
Every hair on your head grows at a different rate, so whilst some grow slower than others ( slightly ) the hair will not sit or move the same way month after month, it needs to be maintained, if you want to grow it longer then keep in mind your average hair grows 1-1.5 inches per month so always cut less than that, if you want to maintain the length then cut what has grown.
Fairly simply? See you every 6-8 weeks