I am having a lot of stress due to menopause and I am unable to sleep soundly. Should I go for acupuncture treatment?
That being said, two years, symptom free, without doing things to keep yourself in balance seems like a pretty good outcome to me. If life is throwing you out of balance, something is always going to come back eventually. This medicine can correct that imbalance, but had you engaged with it as it is designed (to also keep you in balance) by doing regular maintenance treatments after your symptoms went away, they wouldn't be coming back in all likelihood.
So, you have two options... keep engaging the medicine as you are, or only use it when you are feeling "bad" or out of balance, or keep going when you are feeling well to avoid getting out of balance.
Your specific question was how long does it last though... and that is a challenging question to answer. Imagine we went to the beach and where the surf/waves break, we were trying to put a post into the sand. The first time, we drive the post in about 3-6 inches into the looser sand... and the post will stay perfectly vertical for about 3-7 days, but eventually, the waves and shifting sand will push the post over... so a week later, we go back to the beach and push it in a bit further... 2-3 more inches into more packed sand.... but the waves, they never stop. Some days, they are calmer than others... some days, the waves are very rigorous, even overwhelming to the most strongly inserted post...
The waves are stress, eating foods that make you sick, not sleeping enough, etc. I like this analogy because those things never stop... And the times we set the post are when you come in to get put back in balance via a treatment. It also indicates that when there is a lot of destabilizing activity in your life, you may need to come in more to offset that.
Nothing lasts forever... all things are impermanent. My advice is get back into your acupuncturist's office asap. Hope that was adequately explained and do let me know if you have any further questions.
I have never heard of anyone being severely harmed from acupuncture performed by a licensed, fully trained practitioner (beware: chiropractors, doctors and physical therapists can often do aspects of what we do with significantly less training).
Personally, I prefer Japanese style practitioners and those familiar with the work of Richard Tan for pain and tension treatments. Hope that is helpful!