To coupon or not to coupon,that is the question

I watched in awe a program on TLC, Extreme Couponing. I like a great deal as much as the next girl but this is way over the top. Thrift is in my DNA however a 30-40 min grocery shopping adventure is my limit. Buying some things in bulk make sense but not everything. My trips to the warehouse club are twice a month, and with a very specific list. There is only so much room in the house. I also browse the weekly sales flyers for the grocery store; there is one store I prefer over the others. I see no sense in spending valuable resources such as gas and time shopping loss leaders. My usual savings is 25- 30% with sales and coupons,and very little effort on my part. Time is money they say. There is no such thing as free anything, these shoppers are spending their time in order to save some $. I figured out that if I spent the amount of time on the couponing and shopping thing I'd actually be losing money as the time would be take from from my billable work hrs.