I don't think I'm extreme but here's what we do:
I wash out and re-use baggies and Ziplocs that haven't had raw meat or anything greasy in them. I'm also a member of the Redneck Tupperware club.
Use our wood stove exclusively for heating the house. We get free wood so the savings are huge! We built our house with an eye to keeping it cooler in the summer months (deep porches, high ceilings, brick floors) and only run the AC at night.
I wash all of our laundry in cold water and only use the "recommended" amount of detergent for DH's (dirty job) and FIL's (incontinent

) laundry. The rest of the stuff gets washed with about 1/2 that amount. Same with the dishwasher. I use around a tablespoon and the dishes come out fine.
I hang about 90% of our laundry out to dry. Undies and towels go in the dryer.
I buy almost all of our meat/chicken on sale. Last week Albertsons had their 93% lean gr. beef for $1.99/# so I bought 20 pounds of it. I buy that much chicken when the boneless/skinless breast drops to around $1.69/lb. I stock up on frozen veggies when they get cheap enough too.
We eat at least two meatless/near meatless meals each week.
When the kiddos were young I bought most of their clothes at garage sales and consignment shops. Now in their 20s DS shops the Goodwill but DD has become a complete high-end clothing diva.
I do the CVS ECB roll to keep us in toiletries. I can't remember the last time I paid real money for deoderant, toothpaste or shampoo. I take care of my FIL (84 w/Alzheimer') so I buy lots of adult diapers and Boost which usually have a good ECB return and that helps.
We barter for a few things including our mechanic, lawyer and dentist.
Like I said, nothing too, too frugal but every little bit helps! My brother, whom I think
is too frugal, takes it over the top for me. They have an elaborate sponge/dishrag system to avoid using paper towels. I mean like 5 different sponges and 5 different dishtowels, each with a specific use. He also practices the "If it's yellow, let it mellow" system.
Jennifer