I've only changed jobs once, but I do talk to enough people who are responsible for hiring to know some of the thought processes. Potential employers want to k

I've only changed jobs once, but I do talk to enough people who are responsible for hiring to know some of the thought processes. Potential employers want to know your salary so that they can avoid paying you more than required. What's the required amount? The benchmark that's informally thrown around is 20% more than the last pay. It seems that's the magic number to convince people that it is worth the hassle of changing jobs, trying to fit into a new environment... One thing they (the hiring people) also like to know is how long you stayed at a job. Using industry standards for yearly increments, based on your past salary, they can guess your starting point or even guess whether you have had any increments. What they will then do is make an educated guess whether you are a sucker for punishment. If they can tell you've been in a job for some time without any pay movement, they've won. They know it must have been some tremendous push factor that made you want to leave, something along the lines that you're tired of not getting more monetary compensation or job satisfaction has fallen till unspeakable lows. Power in the negotiation swings to their side. I think when negotiating anything, it is always best to reveal as little as possible. Your past salary is one of them. On another note, and this is anecdotal evidence - employers who pay just enough for you to jump ship and join their company and NOT pay you for the value of the work you're about to do or that they know you can contribute, are most likely employers who will bleed you to death in the work environment.