Do I mention a health condition before or after we agree anything?

I have a condition I manage daily. It is under control, it does not stop me doing anything, but it does mean there are days I need to be able to unlock without a discussion, and there are medical appointments where the device has to come off.

I do not want to open with it, because it is not the headline of who I am. I also do not want to agree to a set of rules and then start asking for exceptions in week two, which would look like I was wriggling out of things.

When do people raise this sort of thing?