I adore having a folding treadmill at home, because, living in a smaller space, I can easily stash it away or bring it out for a go. And this time of year, when there's sleet and snow? I don't want to miss out on a workout. If you're like me and you want to be able to run a treadmill at home, but you can’t give away valuable space to a huge piece of fitness equipment? We get it. There’s a solution, though: A folding treadmill gives you the ability to pack up and store your ’mill between runs. Their compact size and light weight comes at a cost: They often don’t have as many convenient features we expect from a top-of-the-line model , nor do they offer huge inclines and top speeds. That said, most can do the basics effectively when you need them, then fit in your closet when you’re done. The best folding treadmills, as we see them, offer a range of sizes and prices for casual runners and athletes in training.…