How often do you really need to trim hair? Even if your hair is damaged a little, is it possible to to keep that damage from getting worse and just let your hair grow? Thanx for any help! 

I do 6-8 weeks because I get fluffy ends.  For me it is a style choice.  It makes my hair more manageable, and it also keeps the ends blunt.

The tapered look (fairy tale ends) doesn't look very good on my hair, I don't think.

For me, 3 months of not trimming is REALLY pushing it.

Some don't cut, or just S&D.

I dust my hair about once a week, but then I only cut damaged or split  hairs individually. I have done only one "real" trim that reduced length this year, and am planning to see, if my hair will like only two trims a year- schedule.

If you don't want the damage to show but want length-reducing trims as seldom as possible, I recommend regular dusting sessions where you snip away damaged hairs. You will notice then, when your ends start to look like they need trimming- I'm almost certain you will be happy with trimming only once in three months, half a year or even more seldom.

for looks and freshness i trim monthly. every time i push it further i just end up cutting what i would anyhow have cut off on a monthly basis. i think it's really the least traumatizing way to maintain equally thick ends all the time. some people only cut 1- 3 times a year but you need really to cut of several inches to get those same thick ends back. i just cut 3-5 mm each time. and i'll be cutting 1/2" once i reach my goal.