What makes sense to do personally is very different from what makes sense to research as a medical device or drug candidate. If a therapy has a 10% chance of extending lifespan by ten years, it's marginal for any particular person (given the current evidence), but a great candidate for a clinical trial.
Oh, I don't disagree. There's the entire burgeoning field of nootropics from which you can pick and choose as many supplements / drugs as you could want to test. An interesting point you might find, is that the nootropics which often have the greatest effect are the ones that help to deal with one or more of the items listed above.
For example, looking at some of the most common "life-extending / anti-aging" supplements people use which might hold promise of clinical efficacy:
[melatonin] -> proper sleep (usually there's an underlying issue of anxiety, stress, bad posture, sleep apnea, etc. that's being supplemented here)
[an innumerable count of different micronutrients] -> complete diet (those that see the most benefits are people that have deficiencies in those areas whether due to poor diet or genetic mutations from birth that lower efficiency of production but perhaps aren't so noticeable that they result in life threatening effects)
[metformin] -> intermittent fasting (which really ends up being the process of autophagy that you want to occur)
