Not too long ago, I bought a "new" 1982 240D. I changed the oil 50 miles after I picked it up (Mobil1 15-50) and drove it 1000 miles home, plus another1000 miles. Then, I was driving it to Florida, from Michigan, 3 K round trip, so I changed it just before I left (Delvac1). Got back and decided to change it again (now it's permanently on Delvac1). These "early" changes were done with the idea of cleaning out the engine--the original owner used only dino and the records don't show which brands or weights.
Now that I'm back to ordinary driving with two early "clean-out" changes, I'll revert to 5 K changes, which is what MB recommends. Any more often and I figure I'm wasting money as well as using unnecessary amounts of oil.