SURVEY - Brake replacement, when & why?

Given that the replacement of brake pads and (particularly) disks is not an exact science, I thought I’d start a quick poll on when (ie. how many miles/trackdays) and what lead to replacements (eg. poor performance, overheating, etc).

Thanks in advance for sharing.

For starters:

I replaced my standard pads for Pagids after my first trackday at a couple of thousand miles. They still seem to have lots left on them after a further 7,500 miles and 5 trackdays but they can now feel spongy on track (as discussed elsewhere).

My disks have just reached the minimum recommended thickness (24.9mm, 2.5mm of material for pads) but look fine, no cracks or scoring, and don’t warp.

Just done braided lines and SRF.