If the person has the same title at a company after 4+ years (unless they are already in a lead/senior role), it's a bad sign. If this is in the first 10 years of someone's career, it tells me they might only be doing enough to get by. Whether it's because they a) are not ambitious enough, b) aren't talented enough, or c) the company they work for is terrible at recognition/promotion is something that I would have to find out during an interview (if everything else on paper looked ok).