I have a couple pair of heavy weight Patagonia fleece pants. They are not inexpensive - probably close to $100 per pair these days - but will last a lifetime (or nearly so), so they are a bargain in the long run. Mine are at least 15 years old and I wear them on cold days here in Montana during the summer, as well as during the winter, and they are still almost good as new. I also know from experience that if any Patagonia product fails I can send them back to the company for repair or replacement.