What if anything should I be doing to help assure a long useful life from my sunroof?

Lubricate the tracks! I know two people who have had to replace the motors in their 190s because the motors burned out while trying to pull the sunroofs across poorly lubed tracks. Considering that your car is only ten years old, your sunroof probably still opens and closes with ease, unless the temperature is relatively low.

Lube it and you should be fine.

Thank you for the reply. Which lubricant do you recommend?

I use the MB sunroof paste from the dealer.