Ah okay I think when you said job change I just assumed it meant going to another company, not having a new position or title. I do wonder how quickly you can change positions though. I imagine once you get to senior it's very difficult keep going higher. At least this was what I heard at Amazon.
Do you know if it's easier to get promoted when switching jobs? I have a hard time believing that since I think you would have had to accomplish something significant on several projects to get to principal, but if you switch companies it's very hard for them to truly the impact of what you did.
I think you are overestimating companies... For most of my career (12 companies, 3 of them my own) it has been easier to get hired at a higher position in a different place than being promoted internally.
When you are applying for a new, higher, role having enough experience at your current level, being sure enough of yourself and demonstrating the ability to create value within the test period will be more than enough for most companies out there.
When trying to get promoted internally you have to deal mostly with office politics. In a way, the quality of your work is only a small part. And, if you are good enough, it can go against you, I know people that have been skipped for promotions for years because their managers knew that the whole department depended on them.
Of course, there are exceptions and I admire those companies, but they are just that: Exceptions.
Staying with one company is hard. Especially getting promoted in Amazon, that is crazy crazy hard. Your best promotions are when you are changing jobs, I think the best time is to change when you can get a more senior position with obviously more responsibilities but also more recognition.
In SF this can be achieved quick, enough if you demonstrate your knowledge during the interview loops. For certain positions they also ask for previous experience but those positions more of the management side I think. If somebody walks in and writes good code we are willing to hire even into senior position, I don't care too much about the history. I have seen a candidate walking in to the interview from a grocery story where he worked as a cashier. Not only he got hired based on the interviews but he became one of the top performers on the team.
I think it is definitely easier to get "promoted" by changing jobs, especially if you are in a meritocratic environment, like some of the startups in SF.
Do you know if it's easier to get promoted when switching jobs? I have a hard time believing that since I think you would have had to accomplish something significant on several projects to get to principal, but if you switch companies it's very hard for them to truly the impact of what you did.