17 year old B&O MMC3 cartridge

I have a Bang & Olufsen Beogram RX-2 TT with a MMC3 cartridge. I bought both new in 1985. I played it almost daily until 1990. However for the last 10 years it has gotten very little use. I finally have moved to a house big enough to have a music room and have set up my full system again. My question is... should I replace the cartridge? It still sounds good to me, but I don't have the best ears anymore and I quickly adjust to whatever I am listening to (good or bad). I was under the impression that a needle stylus and cartridge could last "forever." I have cleaned the stylus using Stanton Stylus Cleaner and I used the Cardas Sweep record to demagnetize the unit. I have never had the unit serviced. Any recommendations?

With the abundant hours of use, it is assumable that it is time to buy another cartridge. Also, move up to LP#9.

Just my thoughts.
I would consider it prudent, if you plan to keep that TT to get another MMC Series cartridge, as a spare, if nothing else. I believe that they are out of production, and getting hard to find.
If you can find an audio repair guy over 50, he'll probably be able to check the stylus with a 'scope. Check out www.sound-smith.com for cartridges. I recently bought their custom made SMA-1 for my B&O and am VERY pleased!
I found a unused MMC1 cartridge locally for under $200. Is there any other maintenance I need to do to this TT?

I also got an email response from a stylus dealer who said I could test the stylus with a Shure Test Disc. What is that and where do I find one? Does the Cardas Sweep record do the same thing?

Thanks for all your help.