long lasting cart

Yes, the quality of the diamond is important as is the condition of your records and how you play them. I have never worn out a stylus and I have a medical microscope to keep an eye on them. I have 4 cartridges now and I do give one away occasionally if I decide I do not care for it.
The cartridge I use the most is an Ortofon Windfeld Ti. The best styluses are going to be very small (less mass) and glued right to the end of the cantilever (again less mass) Chakster is right. The styluses with the greatest contact areas will wear down slower if their azimuth is set up right. 
Clean, static free records is the key. I always use a dust cover and a conductive sweep arm. Styluses do not wear out and I never have to clean records. (I do not buy used records) 

mijostyn

Styluses do not wear out ...

There are only two ways to eliminate wear on a phono stylus: Don’t use the cartridge, or find a way to eliminate friction. If you’ve found the latter, then you’ve solved the perpetual motion challenge and can become wealthy beyond your wildest imagination.

I never have to clean records.

Maybe you never remove your records from their sleeves and actually play them, which would also explain your claim that your stylus never wears out. Do you live in a lab-quality clean room? That would also explain how your records remain immaculate. Otherwise, your records aren’t clean and you either don’t know it, or accept that they are are "clean enough."

I do not buy used records

Even brand new records can benefit from cleaning. Have you ever been to an LP pressing plant? You might be surprised, because records aren't made in clean rooms.

Use Stylast.

+1 melm! Stylast can certainly reduce stylus wear and extend life! Same principal as applying oil to a drill tip.

Would a Dynavector Karat 17d2work?