It's a bit difficult for me to know for sure. I believe I had prolonged periods of milder mania at times in my life. Only looking back do I recognize that likelihood. At the time, I lacked insight. I can say that I was mostly or fully stable between the following years:

0-14 years old
17-19.5
20-21??
22? - 23
25-26
27-32?
40 to present (70-80% of the time)