“Take care of your teeth” is my go-to “old person’s advice to young people.” Once you realize that dentists can’t really “fix” (as in permanently fix) most problems with your teeth (that you get one set for your whole life), that 5-10 minutes a day to take care of them doesn’t seem like so much.
Seriously, once you have a cavity, there’s a pretty good chance that tooth will eventually become a crown or implant. Once a tooth cracks, it will eventually get worse and have to go. Dentistry is mostly preventative, and for the most part they can really only apply a band-aid to serious problems.