Lost Savings?

I threw out a coupon book yesterday to replace it with this years book we just bought.
Very few coupons had actually been used. I’m sure I used enough to make up what I spent on the book in the first place but there were a lot more that could have been used at some point but didn’t.
I don’t really tend to buy coupon books. The only reason I buy this one is because it is a school fundraiser and I feel somewhat obligated to. I don’t think I’ve ever intentionally bought a coupon book because I wanted it.
The problem is that I’m not a coupon person, I will collect coupons that are a dollar or more off or a buy one get one kind of coupon however I rarely ever use them.  I mean to use them I just forget. 
Every time I bother to keep a coupon what actually happens is the next time I buy that item I forget I have a coupon and the next time and the next time. Eventually it will get tossed out when I find it expired 6 months later at the bottom of my purse.   
I don’t really consider it a matter of importance otherwise I’m sure I would actually remember to use them in the first place.  The only time I really think about it is on days when I end up tossing a bunch of expired coupons that I’ve had plenty of opportunity to use.
I can’t help but wonder how much money I could have saved over the years if I had actually used all the coupons I’ve had the opportunity to.  A quick flip through last years book shows me a pretty significant number of pretty good coupons unused. One of the grocery coupons alone could have saved me twenty dollars (20% off purchases over $100).
Sure the amounts I could have saved individually are usually quite small but added up it makes a lot more sense to use the bloody things if I have them anyway.  I’m going to try leaving the book in the car this year and seeing if that helps me to use more.  I doubt it but it’s worth a try.