Rega P25 w/orig Exact Cart - good? + mV question

Hi everyone, this is my first post and I'm getting the vinyl bug for some reason. So, I found a Rega P25 that has the original Rega Exact cartridge on it from 2001. The problem is that it's an estate situation and no one who is alive knows anything about the turntable, it's use, hours, etc. Obviously the remaining life on the cartridge would affect the value of the item.

How can I possibly tell if the cartridge still has a lot of life left on it or not? The turntable works, plays, and sounds great today and looks like it's been very well cared for.

And, what would you guys be willing to pay for a Rega P25 with an Exact cartridge on it, not knowing anything about the cartridge?

Also, I've been reading about different cartridges having different mV outputs, and so that raises another question. For now, this deck, if I buy it, would be going into a Yamaha RX-V3800 which has a 3.5mV input sensitivity spec and a 60mV maximum input voltage spec. Is this cartridge a good match for my receiver?

Thanks!