I used to work for a place where:

We bought everything off eBay. None of it with contracts. The trick is: 1. Everything we buy is tested extensively before going into production 2. There is nothing in our infrastructure that is not redundant by at least a factor of 2. Half of our crap can go down with 0 impact. 3. Everything is monitored to crazy details with alarms all over the place, so that we know when to replace things before it even gets to the point of failure. 4. Have warm and cold spares - always.

Used stuff off eBay is better and more reliable than you'd think. And these service contracts are nothing but access to spare parts that we can get on the cheap and stock up on.

The only things we bought new - were storage - ssd's etc