I always followed the 3 rule, along with the education rule.
The education rule: If you are not learning anything at your current employer, it is time to start looking. Maybe not looking hard, but just keeping the ears open.
The 3 rule, at any given company you can only be promoted 3 times. Once you reach that plateua you will probably not be promoted above that in any significant amount of time. Once you have the 3 rule, it is time to start looking for a lateral or vertical move at another company.
I also had somebody tell me once that you will learn everything that a company can teach you in 2 years. After that it is time to move on also, although he worked for a contracting agency so I took it with a grain of salt.
But it does seem to be true.
Vertical moves from one company to another are tough, but still feasable.
As far as money is concerned I have learned that in engineering business, two guys who do the same thing everyday, who even sit in the same office, could be getting wildely different pay ranges. It is all about what you can negotiate.
Cadnutcase
Please excuse all spelling mistakes.