I've never updated my iOS devices... Ipod Touch 5 is still on ios7, while iPad Air is still on ios8. Never saw the need to. Works just fine, and most features were only applicable with Iphones.I used to think refurbished were the best deals you could get on Apple products, at least here in Canada. I recently realized the best deal is actually to buy it the day it's released, at least if you plan to use them until they are obsolete.
For instance, this iPad has been released for 218 days. iOS support lasts about 5 years. So 218/(365*5)=12%. So buying refurbished in this case means getting 15% off a device that's already "12% obsolete". I'd much rather have it from the start and keep it for the full 5 years.
I'd rather take a heavy discount years later, as I can still use it for a good 4 years anyways, and even beyond