The famous quote about frugality "Use it up, Wear it Out, Make it do, or Do Without" applies very well to reducing one's emissions and dependence on fossil fuels. Everything we buy has an embodied energy cost - that is, the energy to make it contributes to global warming. It also has personal energy costs - more of our hard earned dollars means more time spent at work, or more stress over our credit card bills. Frugality and environmentalism don't have a 100 percent overlap, but often, doing the frugal thing is also doing the environmentally sound thing. Everytime we buy new, we say to that manufacturer "Make one more." One more is often too many.
So how do we do this? First, we use things up - we extract every single last drop out of something. That means we scrape the pan thoroughly, so that we don't end up throwing away food. It means we use our thumbs to get the last bit of egg out of the shell - do that with six eggs and you've got the equivalent of another. Take those scraps of ratty old tshirts and make a quilt, or handkerchiefs to substitute for tissues, or cloth tp to substitute for paper, or whatever. Take the time to really get all the use we can out of things. That includes pleasure, time and love - that is, if we get all the pleasure we can from our simple lives, we won't always need more. If we make good use of all our time - rest and work - we won't be running all the time. If we make full use of the love and support of others, we might look up one day and have a community to rely on.
Wear it out. That means making things last as long as possible. That means darning our socks, mending our jeans, reheeling our shoes instead of just chucking them and getting a new pair. The longer we can extend the lifespan of our things, the less we'll need to buy. And with that in mind, it is often wisest to buy things that really last, and also things that have potential for long term reuse or repair. That means wood furniture, not plastic, metal tools, good quality clothing. It isn't always frugal just because it is cheap - we need to start thinking about the whole lifespan of a object from where and how it was made to what we will do when it breaks or is worn out. A wooden bowl that your grandchildren will use is a better investment than 10 plastic bowls that won't last a decade. A wool sweater that can be felted down to fill a quilt at the end of its life as a sweater is a better investment than an acrylic one. Remember the story about the man who had an overcoat - when it wore out, he made a jacket. When the jacket wore out he made a vest. When the vest wore out he made a scarf. When the scarf wore out he made a handkerchief. When the handkercheif wore out, he made a button. And when the button was finally lost, he told the story. There's almost always a little more wear in things.
Make it do. This requires imagination - what substitutes can we find? How can we use something we have, instead of something new? What can I make? What can I do? It requires living life artfully and imaginatively - much more so than saying "oh, I need a new dish drainer - off to the store." We ask children to make do all the time, or at least we used to. Don't have a train set? Use your imagination. Carve one? Make one out of a cardboard box? Pretend? We need to take the same advice we used to give children, and start finding ways to make do with what we have. Most of us have houses full of stuff. Our sense that we need just one more object to make it complete is probably wrong. Oh, there are exceptions - particularly if you've been living a fossil fueled life, and now need to power down. But most of the time, if we just imagined, we could make do with what we have.
Do without. I live in a 3500+ square foot farmhouse filled with books, tools, kids, toys, etc... I've met people who live in 200 square foot huts filled with themselves and a few tools and pots. Many of those people considered themselves happy, fortunate and blessed - so if you can be blessed with 200 square feet, what is the rest doing for me? If you and I can't do without, who can? Before you buy something, ask yourself - can everyone have one? That is, if everyone had one, would it be good for the world? Did my grandmother or grandfather have one? Did they need one? If not, why do I need one? Sometimes you will need it. But surprisingly often you don't.
We all need food, water, shelter, love, education, joy, clothing, some simple tools, good work to do, comfort, support, peace, security, art, imagination. More than half of these you can't buy at any price, in fact having too much can prevent you from enjoying them fully. The rest can be met 90% of the time in our present society with something used, or with less than you thought. They can be met by making things or finding things or reusing things. Doing without isn't impoverishment - it is life as art.