Forty years, in phases
I was born in the summer of 1969 and started working out in 1983, which puts consistent training at well over forty years now. Not forty years of the same thing. Forty years of phases, some of which I would recommend and some of which I would not.
There were the gym years, and a lot of them, in a lot of different gyms, with some genuinely inspirational training partners. There were spells as a dedicated swimmer, then a cyclist, then a runner. I still run a little, though the version of me who thought a fast time was the point has quietly retired.
Since 2012 I have focussed on and studied bodyweight exercise, which is to say callisthenics. It can be done indoors and out, it costs nothing, and it scales from someone who has not exercised in twenty years all the way up to things I still cannot do. That last part matters more than it sounds. A method you can grow into for decades is worth more than one you outgrow in a year.
The other thing forty years buys you is a fairly clear view of what does not work. I have tried most of the shortcuts. I have been injured by a few of them.

