I think accent can add a great deal to a character. I've noticed a lot of differences in accent within Edinburgh and Glasgow depending on where you stay and what conditions you live in. For example someone who goes to Heriots and has done their whole life is more likely to have less of a Scots accent and more of a 'well-spoken' accent than someone who lives in a place like Niddrie. Then again, accent does surpass where you live, it can be affected by who you are around and who you know. I've known quite a few people who live a posh lifestyle but speak almost exactly the same as people who live the exact opposite.