I used the Amsoil system for many years. The oil didn't need to be changed but once a year, if you remembered! There was a huge by-pass filter that looked like a large toilet paper roll. Many oil analysis demonstrated the oil to be clean and in good condition even after a year of use. Guess that huge filter and the synthetic oil worked as promissed. Engine still runs like new(according to a compression test) after 17 years and 170K miles.

Oil filter position in a Mercedes is particularly easy to reach. Why not change it with every oil change?