Recently my brakes had been a little bit spongy, and the handbrake required a lot of travel, so fearing the worst I booked in for a free health check. Not five minutes after dropping it off I got a call saying the reason my car was telling me it needed a service (what? it must have literally started that day as I hadn't noticed before) was simply that a brake fluid change was due - which apparently it does every two years and thanks to the lengthy variable service intervals I have I'd hit this mark outside of the normal servicing. Luckily it's on the list of fixed-price jobs they advertise to try and fool you into thinking owning an Audi isn't that expensive.
And what a difference. I think the very very wet winter hadn't helped and the fluid had probably absorbed quite a lot of water, but now the braking is much firmer, better feel etc.
So that's one more thing going on the list of things I'm getting regularly changed outside of service, especially if the cars been sat around in such wet weather.