In software development, if you don't stay anywhere at least 5 years, you probably have no idea how to create maintainable software, because you've never experienced the consequences of your decisions. So I'd be skeptical of hiring someone for a senior role who didn't have a tenure or two of that length. I also cry BS to people who claim they stopped learning after a year or two in a role. There is always more depth and breadth to what's right in front of you than you currently know, no matter how long you've been there. Thinking you know everything a role can teach you in 2 years indicates you have very little self-awareness.