You’re getting it wrong. Skills may well be malleable, but opportunities are limited. There’s no guarantee that you’ll get the opportunity to use your skills. What if you worked hard to learn a skill, by making mistakes and exerting effort but these setbacks limit future opportunities to use your hard earned skills? If you lose an opportunity due to self-inflicted failure, what’s the difference between someone who smoked pot the past 6 months and you? Instead, look at guaranteed opportunities and limit your skill to those, so that you don’t have to waste effort for nothing.