Given the absence of perfect information our justice system has to convict a few innocent people. Where the optimum of the ratio between guilty going free and innocent getting sentenced? X guilty going free for one innocent being arrested. What's your X?

That depends on which crime we're talking about -- somewhere around 10^6 for illicit drug use, 10^3 for shoplifting, and 10^0 for murder.

When was the last time you used spaced repetition software (Anki, Memosyth, Supermemo etc.)?

Does Duolingo count?

When was the last time you took a Vitamin D supplement?

Given that you also ask about multivitamins, I guess you mean ‘a vitamin D supplement not as part of a multivitamin’, but you might want to say it explicitly.

When was the last time you smoked?

Do e-cigs count?

Language nitpicks: “eat meat [not flesh]”, “ride [not drive] a bike”.