Only you can decide when it is time to cut or trim your hair. If you are having troubles with tangles, follow the suggestions mentioned in some of the other posts - use conditioner, use a leave-in conditioner, try oiling your hair. 

Be sure to trim split ends - if left alone, they will cause more tangles and more splits.

Thank you.  I think that I will not cut my hair.

Dont cut it. It will take 5minutes to cut off but years to grow back. Just go for a trim an inch at the most. Also make sure you use good products and cut of splits at least every month.

I cut my hair and regretted it as what i really needed was a trim not for it to be hacked off. I am now growing out a bob which i hate and have vowed never to cut off more than an inch ever again.

Make your mind up to wear your hair long for life. It can be tempting to just give in but the aremillions of women out there who would do anything for long hair. Why waste years of growth over a week of fustration.