I've got data for W123 disc brakes that may be close=>

Front new = 12.6mm thick
Front service limit = 10.6mm

Rear new = 10mm thick
Rear service limit = 8.3mm

Maximum run out is specified as 0.12mm for both front and back

If your discs are of a different starting thickness then I guess a guide would be that the front and back can wear by about 15% (judging from the data in my Haynes manual I've given above)

'Hope this helps

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!