I took a year hiatus from brewing because My wife and I recently had a baby. Now that it is not as demanding I wanted to start brewing again. I found a kit I had for about a year. It's a vanilla porter. The yeast and hops have all been sealed and refrigerated the entire year, but the LME and grains we not. The room they were in could sometimes get up to 90 degrees in the summer. they were sealed but I'm wondering if it's even worth brewing. Does it go stale?
I would certainly make it if I had it around.
I would get a fresh pack of dry yeast. It has the shortest shelf life of the stuff you have, and is the cheapest to replace. There's probably enough cells there to bring it back with a starter, but I wouldn't feel bad about throwing away a kit yeast.
Steeping grains, like Crystal/Cara grains, are just fine. The sugars you want from them are already converted and caramelized, and they'll keep for a long time.
LME, according to Breiss at least, can be stored at up to 90F for 24 months. So 12 months with temperatures topping out at 90F should be fine. It does darken with age and in warm conditions, but who cares for a Porter.
The hops are fine as long as the have been in their original packaging. Hops are flushed with nitrogen and vacuum sealed at manufacturing, as long as the seal is kept, they'll keep for a long time. Oxygen ruins them fast though, so if the packaging has lost it's seal, it might be time to get a new pack. My very unscientific and probably too conservative test: Is it still green? Then it's probably fine. Is it starting to turn yellow/brownish? That's oxygen doing it's thing, get a new one.