Yes, that's a concern for me too, I'd like to retire early but healthcare has me wondering about getting a job as a teacher or something just to make sure I can afford it if I get cancer at 55.

If you don't have much income, healthcare.gov plans are pretty cheap.

Some people will just risk doing without. Most will be fine; that's how insurance works.

if you're in the US, ACA is an option, but it'll be expensive if you don't qualify for any subsidies.

I live in the UK :-)