It all depends on your shopping habits and the ability to remember you have those coupons. For example, driving an extra five miles away to save one cent per gallon for gas is inefficient. Your time is worth more and you will likely spend more money in gas trying to get to the gas station. You must weigh the alternatives.
For example, one main reason they offer coupons is to entice customers to either purchase something new or to try a new brand. If you are comfortable with the products you already buy and rarely get coupons for those, then why bother. The key on coupons is not to get suckered in and purchase something you do not want. The biggest thing, people get a coupon and then forget to use it and then the company is even more excited since it made even more money from you.
There are some obvious times when coupons come in real handy!
1.) Babies: When you have a new child you will receive coupons upon coupons for every product available. So find out which one and use the coupons, for the first few months formula and diapers will be nearly free!
2.) Eating Out: If you like to try new restaurants then save those coupons. There are always new coupons in the mail from prospective new restaurants that want your business. Just do not be shy when you go the the venue, use the coupons and save. You should not be shy in handing the waiter or waitress a coupon.
3.) Retail Stores: They always offer 10% discounts and other various coupons. Such as Joanns Fabrics, they give coupons in their mailers and via email every month and there is always a 40-50% off coupon for one item. So wait for the coupon and save big time.
4.) Bargain Shoppers already save more than the average user if they stick to relatively few shops and pay attention to the news. I personally shop at a discount food store. It is 20+ miles away from my home which sounds far, and it is. But 20 minutes to save $150 in groceries is worth my time. If I get coupons I save even more than the usual(We purchase two weeks worth of food at a time).
Just on the above points my family and others save a few hundred a month on products they already purchase. This is critical for low income or those on tight budgets. For us it comes as savings for a trip every year. You make the decision, coupons are valuable depending on how much you value your time and money!