I would think he means senior in terms of a certain quality that I'll describe, rather than "can credibly get senior title", which is really just a function of

I would think he means senior in terms of a certain quality that I'll describe, rather than "can credibly get senior title", which is really just a function of the job market. Senior to me means: - Can dig yourself out of any hole. If you need help, you already have contacts who can point your way. If you need a new language/OS, you are able to understand some things immediately, but you will also know some specifics within a few weeks, since you've seen something similar. You know how to use the internet to find out about anything you come across. Your need to ask new SO questions is absolutely minimal, you can piece things together from other people's questions. You have experience outside of your area: if you're a backend dev, you can still whip up a basic web page, if you're a web dev you still know a few things about memory paging. In either case enough to know where to look for details. - Everything that's industry standard you've either played with or heard of. You've heard of the variants of similar things (postgres, MySQL, Oracle). - You know what the likely architectures for problems are. You know where the landmines are. You have a good idea about what kinds of requirements will blow up the budget. You know which parts are critical and which are peripheral. - You can express why one choice or another is preferable. You understand the tradeoffs in the design. You can translate between business and software land. This last point btw is also the difference between a good lawyer and a not so good one. Given this amorphous mass of vague seniority requirements, my guess is it takes most people 10 years of full time work. You need some time to move around projects to get some variety, and you need time to mature both technically and emotionally. You need time to meet people and get to know them on a technical level too, it's no good just to know other fresh graduates, and realistically many of your matured dev contacts will be people you met early on. I would also say that it's possible to go 10 years without getting all this variety, which is probably a commonly pointed-out thing. But also IMO once you reach this point the curve flattens: your next 10 years are unlikely to expose to something vastly new, and so a 10-year senior and a 20-year senior are not hugely different from each other, though both are vastly different from a 5-year dev.