[ryanianian]

Don't "need" to change jobs, but ensure you're not complacent, under-paid, or unemployable elsewhere. Best way to do this is to regularly interview.

I advocate every 6-12 months, even (or especially if) you're happy where you are. There's virtually no downside to doing this except for an unpleasant vacation day. Worst case is you still have your job you like. Best case is you get an offer that gets you a raise (either where you are or with a better company).

(Doing this I've gotten about a 10% raise every year for the past ~8 years - sometimes changing jobs but usually just presenting an offer to current employer - and I'm not a rockstar interviewer or anything.)