How would that work? Very few people stay in a tech job for 10 years. I stayed in a software job for 9 years, until I was laid off, and that's extremely unusual.
Normally, the exercise window starts when you leave and lasts 90 days. The 10 years works the same way, except much longer! It has nothing to do with how long you're at the company (although some companies only trigger an extended window after you've hit X years).
Most startups offer a 90 day window to exercise after you leave. Some companies have extended that to longer (caveat being they convert to NSO grants after 90 days).
How would that work? Very few people stay in a tech job for 10 years. I stayed in a software job for 9 years, until I was laid off, and that's extremely unusual.