I'm not offended by it at all but I guess there's also a chance they're attempting some mental maths around how much money I must be making, which isn't anyone else's business except HMRC.
Mental maths, exactly.
There are two subtexts that make this question annoying:
1. The mental maths and trying to figure out how much money I'm making.
It often comes with no appreciation of the effort, risk, mental, physical and financial costs that this job requires.
2. That they somehow find it's appropriate to ask this question.
I agree that people are curious and it can be part of general chit-chat.
I do wonder though, would these same men walk into any other establishment and ask about the cost of the rent?
Do they go to their dentist and ask about the rent?
I would class this question as the same as asking about my age for example. Would they ask a woman in other circumstances about her age?
The way I see it is that they don't think the same level of courtesy applies to a sex worker and to a civvy woman.
But then, I'm not on a dating scene for example, so perhaps I have unrealistic expectations.
(* Adding to this - it's like they feel it's okay to ask me a question but somehow don't expect they can be asked back the same question.
Like I'm a little girl that can be asked questions and is not expected to talk back.
So i said are you ok me asking what you earn per month and how much you spend per year on escorts.
This.)
Sometimes I answer, sometimes I give them a rough idea and sometimes I just tell them it's really fucking expensive
This is a great answer. I would add - "It's really fucking expensive. Like me."