Started on 30k progressed to 60k in London. People who stay in one place for more than 1-2 years without decent raises do a bad favour to everyone except for employers. Do move around and get what you deserve along with varied experience! Companies do shell out on contractors when there is a need and can keep them for years. I think it is some sort of misrepresentation that leads people to think that it is OK to pay less then 50k to a decent dev in London.
Yes, you need to use your best judgement. I would spend at least a year at each place depending how good it is. I think changing 4-5 jobs before you turn 30 is good enough, would've looked weirder when you are 40. It should come across as normal during interviews as well. How do you know you are doing what you really want/should be doing if you did not try multiple things? How do you know if a small/mid/large company is your favourite environment? Have a story/plan and have some achievements at each place, always leave on good terms. PS: contractors move around at least once a year on average and it is considered normal (unfair).
I wasn't trying to argue against you, I was just asking for opinions on the limits of changing jobs too much. My own estimate is something like 1-2 years minimum per job.
When interviewing candidates, staying under 6 months makes me slightly concerned. But only slightly; there are many good reasons a good developer might only stay somewhere briefly.
