Non-competes generally require consideration, time limit, and geographic range to be enforceable. Again rules vary by state.
In 40 years working as a programmer in multiple states I can’t recall signing a non-compete more than a couple of times. Obviously lots of people with non-competes change jobs all the time, so I don’t think it’s a big problem unless you actively harm your former employer.
That said, if you were the lead designer at a company and held multiple patents, and another company offered a lot of money because they wanted to steal the secrets ... well that would go to court.