In the US, thats not generally true. It takes longer to prep from scratch if you have a young family. If you have an older family (and are even older yourself) that constraint is reduced. Realistically you can prep doing a few questions a week, it will just take longer. It’s not pleasant. But it’s more about the commitment, the plan, and enough research to justify it. If you can reasonably expect a 50%+ pay increase and that would translate into a better life, most people at most ages can make time. It’s about experience and practice with generally well known algorithms on well known problems. It’s not rocket science or intelligence nor nearly as much prep as many other high paying jobs (my MD took a decade of study for instance). Yes, annoying as hell. But not insurmountable.