Your hairdresser told you that coming in for a trim every six weeks will make your hair grow faster. She said it so it must be true, right?
Wrong! First off, you got duped and she's eating up your tips. Second, if you want your hair to grow faster, well there is very little you can do – unless you can change your genetics that is.
Hair grows roughly half an inch per month, slightly more in the summer. This is whether you get trims or not. So if you are trying to grow your hair out but are getting it trimmed ½ an inch every six weeks, then you won't get very far. What a good trim does do is eliminates split ends which, in the end, does make hair look better and healthier.
So if you're growing your hair out, the best way to go is to skip the salon until you reach your desired length. And if you're worried about too many splits end's during your stylist separation period, than lay off of the hot stuff (ie: curlers, irons, blow dryers) for awhile.