I know someone who has followed a career path of frequent job changes (always in the same metropolitan area, mine, the Twin Cities of Minnesota) in computer-related work and who has always managed to make each job change a net raise. He is making substantially more money now than many of his contemporaries who stayed at the same company for years, and has leaped over some of those persons for more responsible roles with more challenge (what you desire) and a better pay-and-lifestyle balance than other people with similar technical skills in the same company have. In other words, it depends. If you make sure to trade up every time you trade, you have set up a ratchet that should make your career better over time.