around 40 or so if you want to get in early or maybe around 45 if you are more conservative. I would say best to start before age 50. Senescent cell clearance would be beneficial early in the 40s in my opinion. Maintaining a cellular environment that as much as possible resembles a youthful state likely could prevent other age related issues from occurring as a lot of this stuff is bilaterally acting on each other to mutually worsen over time.