I think most people fall into two groups, the ones that change jobs every year/every time they can make another dollar, and the ones that stay in one place long past the point when it makes sense for their career. What's interesting about the frequent job changers in our industry is that they are rarely punished, it's almost expected to see a high rate of change and as long as you have the skills (or seem to) you still get the job. On the other hand I don't see much in the way of value attributed to those that show some loyalty/depth by sticking with a job for a duration of say more than 3 years. Isn't that backwards?
Most of that problem is we're all taking a short term view. We (employees) want more money now, managers need staff now, senior leaders want the stock price to go up now. I don't agree with it, but it does reflect the way the world works.
There are benefits to both the short/long term approaches. I have a close friend that had perhaps 6 different jobs in 10 years, the result is he's a very skilled job candidate, has gotten to be good at adapting to new cultures, and the prospect of a new job holds absolutely no fear for him. The downside is that until the most recent job which has been of longer duration, he never got to experience the value that comes with working at the same company for a long time, the business knowledge that let's you propose interesting solutions that would never occur to the 6 month veteran. I've taken the opposite approach, working at the same company (though in several different roles) for almost 8 years before leaving to try a new venture 2 years ago. That long duration gave me the chance to get to know a lot of people and the business in a much deeper fashion and I know that made a difference in the value I could deliver - but I was stuck in one culture that wasn't always as progressive as I would have liked in both technology and overall leadership.
I've thought about all this before, but it came to mind against recently as I have friends working at a company that from the outside appears to be on the down slide - key indicators being recent layoffs, no training, no raises, several changes in key leadership positions, lack of forward movement, and no firm vision. That's my view, not necessarily theirs, but I suspect few would disagree that its the kind of situation that has you wondering - is it time to move?
I always recommend against leaving post layoff - if you survived you weren't in the bottom 10-15 percent, and usually it's a one time layoff. If you see a second layoff within a year that isn't clearly the result of a separate event, it's a sign management is being reactive and unrealistic, so it's time to go then. I can see going without a raise for a year, but past that it's a bad sign, and time to go.
Most people stay in jobs because it's comfortable, benefits are good, and they aren't likely to make much more money somewhere else (most of hit the salary ceiling all too soon). Going to another job is less comfortable, we get less vacation, and we're human - we just don't like change! The only danger in staying is that our skills get more and more situational, not as well rounded as we might wish (or need) them to be.
Once the company appears to be in trouble though, the additional danger is that change may happen on their terms instead of yours. We all work to take care of family, leaving that to chance requires a sturdy fall back plan (money in the bank at least).
I'm probably mixing messages here, so let's recap a little:
Changing jobs is unlikely to hurt your career
Staying in one place is unlikely to net you more money in the long term, or bonus points at the next interview
Don't change jobs as a fear based reaction to an initial layoff
Staying in one place does have rewards worth considering
If we see warning signs we should review our fallback plan, and a good way to assess things is to think - if I interviewed here today would I want to work given the current situation?
I like the benefits of staying in one place even if it means taking a chance, and it's led me to places I don't think I would have reached otherwise.