My experience goes as such -
I call for a quote for a job that is the same as my partner had done the previous week/year and get quoted double what he did.
I call up for a quote where just a description would suffice and get quoted double what my partner gets quoted for the same job description.
My partner = local accent, mine isn't.
My parents, very nice house (the largest) in a village where everyone knows one another, talk frequently and use the same trades people, guaranteed that the quotes they receive are thousands more than others have received for the same/similar type of work.
Even their previous cleaner, on learning they have other properties, decided she wanted to double her hourly rate (was already being paid more than the local average) because, and I quote, "they can afford it".
My parents = large property in comparison to the rest of the area.
Whilst not all trades people are like this, between us we seem to have encountered all of them.