I’m pretty sure the provider will tell the users once they start charging money, they want to convert them to paid customers after all. And migrating a static site every couple of years wouldn’t bother me too much either. If you value the time with your hourly income, it’s probably not worth it, but if it’s fun, it’s fine.
Web hosting is very cheap - especially for static sites. Much easier to pay and forget about it. I've used my provider for 20 years.