14k does seem a little on the light side for rear pads, best part of 30K on the second set does seem more reasonable.
Discs, personally I reckon discs ought to be good for 100K at least but designers don't seem to agree with me
If memory serves, Renault specify 0.5mm wear per side (1mm overall) as maximum wear.
That's a set of discs every time a set of pads needs replacing
Mechanically there is no need for this limit. The true limit is the maximum travel of the piston minus the full wear of the pads plus a safety factor. Which will work out far more them 0.5mm
There is also the worry about physical strength reducing as discs reduce in thickness and too be fair they have to think of one pad sticking and load being one sided.
Thermally, it's more difficult and is based on heat gained versus cooling area and volume to absorb the heat and again they have to consider worst case.
There is also the case that with every available ounce being saved for fuel economy that discs and many other parts are far skinnier then they used to be.
But I still wonder whether this is a true safety consideration or a money spinner.
I don't know so the only thing I can say is go with the specs but don't have to like em