Regarding your worn disks ....
I got this from this forum, not scientific but pretty darn close:
Brake disk thickness- Penny Dime Nickel
If your brake disks have a lip whose thickness is no more than that a "Dime" - you might be able use them again.
"Pennys" - its about time to change them
"Nickel" - Regardless brake light or not, hurry up and change em'
BTW, here are the official thicknesses of the US coins:
Penny 1.57 mm
Nickel 1.98 mm
Dime 1.35 mm
The obvious note is there are two sides to a brake disk.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)