Is it permissible for a female to trim ones hair?

I have researched various sights and they all come to the conclusion that a womens hair (on her head) should never be cut unless when on Hajj. 1.do you agree with this? (I understand that they come to this conclusion due to the fact that most ladies cut their hair to imitate a hair-style designed by Kufaar.) From what I understand a muslim ladies hair must cover her chest so 2. Would it be permissible to trim off split ends to maintain healthy hair (and not to imitate any particular hair style)?