Can I still wear this 7 year old helmet?

I have a Suomy Spec 1-R helmet that is in great shape, though it's more than 7 years old.  I know you're supposed to replace your helmet every 5 years or so, but I only wore this helmet for one season, and for the past 6 years it has been sitting in a dark, dry closet in its helmet bag.  I know that the plastic, foam, glue, resin, etc. in the helmet can still deteriorate over time without being exposed to tons of sweat and sunlight, but surely at a much slower rate?  Maybe my helmet is actually in similar condition to a helmet that is just 3 or 4 years old?

I would really hate to have this helmet go to waste, and have to shell out several hundred dollars for a new helmet of similar quality.  Would you still wear this helmet if you were in my shoes, or would you bite the bullet and get a new one? Thank you, I appreciate your opinions.  

We would replace it. It's not just sunlight and sweat...it's basically time and exposure to the atmosphere that causes eventual degradation.  

Virtually every manu. will say that 7 years is end of life for a well stored NEW helmet. The weak link in the EPS. A friends sister was a passenger going down at 25mph in a very old helmet, she suffered MAJOR brain injury, 3 weeks in intensive care, limited use of her right arm (brain issue not the arm)and extensive scaring all over her head.

Play it safe - ALWAYS! Plus many of the new Carbon helmets are now affordable and crazy light.  

Thanks for your replies. lightspeedR6, that's a terrifying story. I'll start saving my pennies for a new helmet!