Have you ever worn fleece-lined pants? They are really warm and comfortable. However, there are a couple of drawbacks. First, fleece-lined jeans are expensive. A pair of fleece-lined jeans costs $40 to $60. Secondly, if you get hot in the middle of the day you will have to change pants. This could be inconvenient if there is nowhere to change.
I hacked the fleece-lined jeans by making the lining into stand-alone liners. This way I am able to wear the liners under all my pants. Also, if I get hot in the middle of the day, I can just untie the ties, take off my shoes and remove the liners without taking off my pants. It's so convenient for outdoor activities such as camping, hiking, motorcycle riding, football games, yard work, etc.