Depends fully on your way of driving and if you change the pads in time.
If you do a lot of full force brakes, the discs will heat up enormeously. If
you keep your foot on the pedal after coming to a standstil, the disc will
cool down unevenly and warp as a result thereof (the not covered by the pad
part will cool down from the air, the covered part under the pad will stay
warm)
Stopping in a pool of water will do even more damage due to the increased
cool down.
Best thing to do is brake by letting the pedal loose a few times; much less
heat will be brought into the disc.
On the other hand, a worn pad, will damage the disc and/or make the grooves
even deeper. If a pad is worn to the steel backing, it will even be (much)
worse.
Check the pads between service (i.e. ervey 5000kms) on a grooved wear
pattern and replace them befor the friction material has been worn evenly to
the groove in the middle of the pad.
For a hard driving style 30K miles is nice for the front.

Signature
Ciao from Holland
AlfistaGJ (Gert-Jan)
Rosso Radicofani GT 2.0JTS (2005)
Golden Montreal 1428700 (1973/4)
> On this subject of discs, can anyone tell me how long they would expect a
> set of front discs to last.
[quoted text clipped - 7 lines]
> 156 2.4JTD V1 (2002)
> To reply: remove nospam. from the address
Simon C - 06 May 2005 13:59 GMT
"alfistagj" wrote in message
> For a hard driving style 30K miles is nice for the front.
Thanks for that, much appreciated.
Regards
Simon C