A bit of a PTTGOYN post this. My van was MOT'd in January and I've done 3000 miles since. At the MOT there was no mention or advisory about brake discs or pads. It just went in for a service at a different garage and I'm informed the discs & pads are almost worn through, way below the limit.
I'm inclined to trust the servicing garage over the MOT place, who were likely either incompetent or lazy, but a past experience with this is always in the back of my mind.
A few years back in the old job/van, it had new discs & pads replaced for an MOT. 6 months later it got a service somewhere else, and they rolled out the old "brakes need done m8". The boss took it elsewhere and they said the brakes were absolutely fine as you'd expect after 6 months.
There are no doubt chancing c**ts everywhere, although I've always been happy with the current place which is long-established with a good reputation. Typically I also needed 4 tyres too so bit of a sore one.