Jazz rear callipers - what a job! I'm a northerner, so if there is 1mm of good brake pad remaining then why replace it???

After my rear discs began rusting and numerous calliper strip and rebuilds, I came to the conclusion that the piston won't extend any further so the rear brakes stop working. That explains why my front tyres wore more quickly than the back.
On (actually) buying new pads, the rear brakes began working again. It was quite a moment when I drove it for the first time with all the brakes working. The car slowed very promptly. Of course I had become used to pressed hard on the pedal. How it passed the MOT I don't know...

So now I will replace the pads at 2-3mm to be safe.
If the callipers haven't been serviced then they could be sticking as a result of water ingress and rust. Servicing opens a can a worms because its a real challenge to insert the pistons through the dust seal. The piston wants to push the seal into the bore. And any tool used to pull the seal upwards mustn't pierce it. I discovered the bent wire tool in the attachment made from 2.5mm
2 T&E cable hooks up the seal quite well. It also helps to have a lot of swear words handy like "you f.. b.." etc

Oh and another thing - the rear calliper pistons can seize as a result of rusting around the dust seal. On British callipers I seem to remember that the dust seal is stretched over a male boss on the calliper body. On the Honda it's pushed into a female socket and then the piston goes through that. This allows water ingress plus rusting between the outer surface of the seal and body which pushes the seal inwards and onto the piston and jambs it. On the British design, rust under the seal lifts it up but it does not push the seal onto the piston.
I use Bigg Red for my brake spares
HTH