I'm pretty sure the only "wear" parts are the seals and oil, both of which should be replaced with a rebuild or upgrade. I had my suspension rebuilt by a local Race Tech shop last winter and just checked the invoice for the list of materials:
Rear Shock:
- Valves (Race Tech sells theirs as a kit with 1 part number.)
- Seal head
- Shock fluid
- Shock spring (optional, but recommended for 185+ lb riders.)
- Shock spring collars x2 (required to fit the slightly shorter aftermarket spring to the stock shock assembly.)
Front Forks:
- Compression valves
- Rebound valves (Note: Unlike the rear shock, Race Tech sells fork rebound and compression valve kits separately.)
- Fork seals (I prefer SKF brand.)
- 5 weight fork fluid.
- Fork springs (optional if you find the stock spring to be soft.)
I paid around $1250 for all of the above, including professional installation which was only $220, or about 18% of the overall project cost. After reading the rebuild sticky threads in the suspension subforum and looking at the photos I quickly decided that was $220 well invested.
Here's a reference link to Race Tech parts.
... and a link to Go Race Suspension's web page with similar overall pricing.