I would have to agree with the points made by the previous gentlemen. The modern car is getting too complex for home maintenance and an MBZ is still worth keeping.
I'm known among my friends and family for keeping my cars for a very long time. Then when I sell them, it is usually to family or friends.... I say all this simply to add that an important factor is pride of ownership. If you care for your cars both internally and externally, 10 years of good service from them is very likely. My average length of ownership is 7-8yrs and I've had the diesel in the family for 18yrs(it still knocks the socks off techs when they see it's condition).
All corporations, sadly DC now also, build with shorter planned obselecence cycles. It is more profitable in the short term to get us to buy again sooner, in the longterm they lose lifelong customers like myself(nothing but Mercedes for 17yrs).
My next car, my step up car, will be Porsche but that's just because a Turbo Carerra has always been my dream. I however think the new SL500 is just perfect and would own one of those if I could afford 100K+ for a car. And, if I had to own only one car, of all choices it would be the E55.
So, I'm not giving up on MBZ, but then again, I care for my cars and pay no attention to FSS except to get some free maintenance!