Peri can last 10+ years (did for me). I don't know how you're going to decide when menopause is there for you? I had heard that a "year" without a period was how you knew the end for sure so I just did that; seems like for the last 2-3 years I'd get several months without a period (think I got 6-8 months between once :-) But finally I had a year and no more periods.

I couldn't tell the difference between peri and the "real" thing though; just most of my 40s were peri. It was interesting to me because my 40s were like my 20s; 30s were my "best"/most physically comfortable "normal" decade. But the 40s/peri were less "intense" than my 20s with only a few more symptoms than regular/getting started? I was a teeny tiny bit more depressed the week before my period, etc. but definately didn't find anything to be "anxious" about.