to add to your pad longevity history:
'94 E320 Coupe Starmark: factory replaced front pads & front rotors at ~63K, currently vehicle has 93K (combined city/highway weekend use), and I'd estimate front pads at 35% w/ maybe 6Kmiles left on them (front rotos still look new)
'72 280SE 4.5: OEM front pads went ~2yrs/30K city/hiway miles
'67 250SE: OEM front pads went 2-3yrs/30K+ city/hiway miles
'73 450SEL: OEM front pads went ~2yrs/20K city/hiway miles
'67 250S: OEM front pads went ~2-3yrs/30K+ city/highway miles
'94 E500 Starmark: currently vehicle has 35.5K and front and rear pads look new all around/ curious to see how long the SL600's last...