It seems like you put very low mileage on your SL500. With only13,000 miles
since 2005, that means you only put on about 2600 miles per year.
With this in mind, I suggest you NOT follow MB recommended service interval
based time but rather base it on mileage. Your dealer is doing too many
maintenance service to pad their income.
With your usage, I'd recommend at least one oil change per year. Even for
your other cars with low usage. The reason for one oil change per year is
because the oil deteriorates due to age without going into technical
details. One of the issue with low mileage is moisture and whatever
contaminants that can't be burned off with low usage.
It is also recommended once a year you drive this car on highway for a good
distance like 100 miles to burn these moisture and contaminants away.
Now, most likely your oil filter will be the 'fleece' type... which is like
$20... make sure it is not paper type which is cheap at $5. With this
filter, you can theoretically just change the oil and leave the filter
alone. Change the filter every other year. Fleece filter does last for
Choice of oil for you is Synthetic. If you do use regular oil, you have to
change the oil twice a year.
Now, I am not sure if you have a fleet of vehicles... if you do, the
maintenance can cost a bit... you may consider having the oil tested by
laboratory for around $20 instead of changing oil... with the lab, they tell
you the condition of the oil and give you guideline on when to change oil...
this is one time testing to give you a basis on when to change your oil for
Now on the other matters such as Service ABCD... I would do it at the
specified mileage stated in the book... Say Service A at around 10K miles...
Service B at 20K miles... It is a nice 'vehicle checkup' for you but you can
delay it a bit longer.
Hope this helps.