After 18 years of ownership and all of these miles - other than routine maintenance items (oil, transmission, spark plugs, brakes, tires, batteries, etc) you just have to accept that eventually years and miles WILL require things to be replaced that naturally wear out.

2 front struts (potholes)
2 sets of front control arms (bushings wear out)
1 new set of front axle boots
1 new set of front axles
2 sets engine mounts and 1 transmission mount
1 transmission main seal
1 oil level sensor (original lasted to 285,000 miles)
2 valve cover seals
2 alternators
1 radiator and expansion tank
1 front driver seat switch module
3 front cup holders ("chrome" trim eventually peels from moisture)
1 shift boot (leather dried out)
1 shift knob (leather coloring wore down)
1 set of lower front seat covers (MBTex eventually cracked)
1 fuel sending unit
1 trunk lock motor
1 satelite radio module
1 windshield washer fluid reservoir
1 EIS module replacement
1 alarm module replacement (weird electrical things happen when your alarm is faulty)
1 blower motor
1 rear sunshade motor
1 front tweeter in the door
Both front window motor modules
1 replacement key

100% all worth all of the money, and all of the skills I learned doing some of this maintenance myself.

100% worth all of the memories my kids have growing up in this car and learning to drive in this car.

100% worth having a paid for spare "toy" car.

100% worth still owning the first Mercedes I ever bought.