Updating OSX in Mac Mini
Apple doesn't support its OSes as long as Microsoft supported XP. 

Wise advice would be possibly "Don't jump right now, but don't leave it too long"

It's always wise to wait until applications are updated to support a new OS &amp; initial bugs are ironed out, so waiting for 10.10.1 would be a sensible precaution, but you don't really want to hold off until it's so out of date that if you upgrade nothing you currently own will run.