Well that's about as varied a pool of replies as I could want, given the question, so thanks! - my official title includes it but I don't use it, to ease the c

Well that's about as varied a pool of replies as I could want, given the question, so thanks! - my official title includes it but I don't use it, to ease the competition - use it when you're smart and fast enough to help & enable others (but you might be a lead engineer or manager at that point) - let it be bestowed from without, and by the way it's dependent on the context (tends to mean more the bigger the company, and is usually stated in relation to others around you) - several more saying let it be bestowed from without (including possibly by asking for it to be bestowed) - I use it only to game clumsy recruiter searches - I guess I'll add my own, which is kind of half-joking: Once you've got 5 years of experience you're "senior," and that's because, as Uncle Bob Martin pointed out recently, the number of devs in the world doubles about every 5 years. Which means if you've got 5 years of experience you're above the median; you're more experienced than half the people out there!