Out of interest do regret staying in your first graduate job so long? (do you feel you otherwise could have increased salary quicker? )
What field you in? IT I'm guessing?
I work in mobile software development.
Software development is the kind of field where someone with three years experience in a certain technology is considered senior (rightly or wrongly). If all you care about is money then there's no point staying in your graduate job beyond the first three years.
I could have moved sooner but mobile only started to explode when the iPhone was released in 2007. There weren't very many mobile jobs before then so I would have had to have moved fields to find a job. A lot of the graduates who left before me went into banking and I have zero interest in that.
So, no, I have few regrets but for very industry-specific reasons.