I've generally had 10+ year tenures other than a return to school that was basically always in my plan and dot-bomb (leaving a company I wasn't really a fit with anyway). But, yeah, I've always been ready to move on at about that ten year point which is actually fairly long by a lot of people's standards in the tech industry.

I do disagree though that, unless there's some actionable change that would specifically benefit you like more money, my answer outside of private conversations with people I know well is going to be some variant of "time for a change." Anything else just invites arguments and conversations I don't want to have.