I'll either politely refuse to answer or if I have thought about it beforehand then I'll give a number that guides them towards the salary I am looking for this time around.
I don't really mind the question. It's a little rude and it's only asked to get a gauge of salary expectations so why not ask what the current salary expectations are directly.
I've actually flat out said "that it isn't really relevant, but can you share your range and we'll see if that makes sense once I learn more about the role?"
It has worked a few times. Some get surprised when someone tries to flip that on them. The ones that balk get dropped from consideration.
That's always a possibility. I usually frame it as something more like "I still need to learn a lot more about this role in order to tell you an amount that would make sense for me, and you still likely need time to learn more about what value I can add. If you can share your range, we can make sure we're at least in the right ballpark, and if it makes sense to move forward I'm confident we can arrive on a comp package that works for everyone."
Very often this question gets asked on initial screener calls. They don't know how to really evaluate you or what you bring to the table, and you know whatever high level thing the recruiter was told about the role. The purpose of the call is to determine in the quickest amount of time whether it makes sense to move forward to a deeper, more formal discussion about the opportunity with the people actually qualified to discuss the role at that level (hiring manager, etc.). Make it clear that you are interested in the entire comp package and not just salary. I haven't really had that much resistance to this.
At the end of the day it is on you to do your research on what they need to pay you for this to make sense, and be happy with that number. If they won't go for it, you tell them what that minimum happy number is, and if they won't get there one way or another (extra vacation, etc.), then you need to pass (assuming that is a realistic option for you).
I don't really mind the question. It's a little rude and it's only asked to get a gauge of salary expectations so why not ask what the current salary expectations are directly.