U stay on HRT for as long as you require it. Years ago we were advised to stop all treatments at I think it was 60, but if a regime works, why stop? Many women continue with treatment for ever. The way to find out if 1 is 'out the other side' is to stop HRT, however, if symptoms return ........ once a regime is found to suit, many keep on it.
I have been lucky. Throughout my menstruating years I had heavy, clotty, excruciating periods. Once peri-menopause began: The Change: I knew that periods would lessen and mine certainly waxed and waned. I was aware that women experienced hot flushes, however: any of the other symptoms were never mentioned . Especially anxiety and vaginal atrophy.
Some find that keeping a mood/food/symptom diary useful. It's natural though can throw up lots of symptoms - ask away.