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How many years can you add to your life?

Eleven changes with published effect sizes, what each one is worth on its own, and the reason the second change is always worth less than the first.

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See your own numbers. One lever is free to try.

The eleven levers

What each change does, and where the figure comes from

These are the changes Yorick can model. Each one rewrites a single answer to a realistic better state and re-runs the entire calculation, so the years you see are correct for your age and for the rest of your answers.

Quit smoking Moves you to quit before 40 if you are under 40, otherwise to quit at 40 or later. Cessation before 40 removes about nine tenths of the excess risk. Jha et al., NEJM 2013; Doll et al., BMJ 2004
Reach a healthy weight Recomputes your body mass index at 22.5 while holding your height. The heaviest category carries the largest single non smoking penalty in the model. Global BMI Mortality Collaboration, Lancet 2016
Upgrade your diet One step up the ladder, from western to mixed, mixed to mostly healthy, mostly healthy to optimal. The full span from worst to best is about seven years. Fadnes et al., PLoS Medicine 2022
Invest in your people Moves social connection to strong. Isolation is one of the most underrated entries in the whole table, worth about 3.7 years. Holt-Lunstad et al., PLoS Medicine 2010
Move more Sedentary becomes meeting the activity guidelines; anything already there becomes high. Walking counts. Moore et al., PLoS Medicine 2012
Fix your sleep schedule Moves you to a regular schedule. Regularity outpredicted duration in the 2024 cohort, which is why it is a separate question. Windred et al., Sleep 2024
Sleep 7 to 9 hours Moves sleep length into the optimal band. The association is U shaped, so this lever also helps people sleeping too long. Cappuccio et al., Sleep 2010
Tame chronic stress Moves chronic stress to low. Depression is scored in the same group, so the two do not both count in full. Chan et al., World Psychiatry 2025
Train strength twice a week Moves resistance training to regular. Smaller than cardio in life years, and one of the cheapest to actually do. Celis-Morales et al., BMJ 2018
Cut back on alcohol Moves you to light drinking. There is no bonus for moderate consumption in this model, because the 2018 analyses did not find one. GBD 2016 Alcohol Collaborators, Lancet 2018
Sit less Moves sitting time to the lowest band. The smallest lever of the eleven, and the one most people can change today. Ekelund et al., Lancet 2016

Why eleven levers do not add up to eleven levers

This is the part most calculators get wrong, and it is the reason a naive sum can promise you forty years.

Take a person who smokes, eats badly, never moves and is isolated. Read each published effect literally and you might add ten, seven, three and four for a total of twenty four years. That number is wrong, for two reasons.

The studies overlap. When a cohort study measures what a poor diet costs, the population it measures also contains people who do not exercise. Some of the diet effect is really the inactivity effect wearing a different coat. Yorick handles this by putting correlated answers into one group, letting the largest effect in a group count in full, and counting every other member of that group at half weight. Diet, body mass index and type 2 diabetes share a group. Activity, strength training, sitting time and physically active work share another.

Life expectancy has a ceiling. Even after grouping, the combined total is damped: it moves linearly up to eight years and is then compressed smoothly toward a hard cap of 18 years. And the whole adjustment is scaled by age, at full weight around 35 and less than a third by 90. A 70 year old who fixes everything gains real years, but not the same years a 35 year old would.

The practical consequence: in the app, adding up the individual lever gains gives a larger figure than selecting all of them at once. The combined figure is the honest one, and the app labels it as overlap corrected rather than quietly showing the bigger number.

The first lever is the cheap one. Because the largest effect in a group counts in full and the rest at half weight, the single biggest change you can make is worth roughly twice what the same change is worth once you have already fixed something related. If you are going to do one thing, do the largest one.

Ordering, and the reach an age question

Knowing what each change is worth is not the same as knowing what to do first. Yorick Pro includes a Lab where you stack changes and watch the date move, and a solver that works the other way round: name an age you want to reach, and it searches for a small set of changes that gets you there, picking the largest marginal gain at each step. If even every lever combined falls short, it says so and shows you the ceiling instead of inventing a path.

That refusal matters. A tool that always finds a way to give you the answer you asked for is a tool that has stopped calculating.

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Free result and one free lever. All eleven for $4.99 once.

Nothing on this page is medical advice. These are population averages from published research, applied to a questionnaire. Talk to a healthcare professional before making health decisions.

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