Quoted from IdahoRealtor:

Mu first reaction to your post was an eyeroll, but I'm in a good mood tonight so I'll try to be helpful for once.
1. Shed your stress. These are commercial machines built to last tens of thousands of plays. Most homeowners never hit 1000 plays and are needlessly concerned due to simply not knowing better/being new. Perform basic maintenance as described below and you'll be fine.
2. For you, no need to buy any replacement parts.Waste of money unless something breaks. I keep some replacements for wear and tear items on hand, but I have 12 pins, including several much older than yours, and also used to operate 8-9 pins.
3. Replace the balls every 1000-2000 plays as they will get dinged up.
4. Rebuild the flippers every 5000-10000 plays, or as needed.
5. Clean the playfield every 300-500 plays. All you need is Simple Green and a microfiber rag. If you want to add some protection apply some (a little goes a long way) carbuba paste wax after you clean the playfield, but be ready for the game to play much faster, for better or worse, due to rediced friction. You can polish out fine acratches in your playfield with Novis 2 and a microfiber cloth. Do not do this every cleaning. Once a year is plenty for a home use pin.
6. If something breaks you can email Stern tech support for help basically forever, or get tech help on pinside, but try Stern first since it's free. There are also pinball techs in most areas that can take the fixing side of the hobby off your plate for a few bucks.
7. When you go to sell someday nobody will care whether your pin has 500 plays or 5000 plays, so play the hell out of it.