One big reason is the weather. I run outside all summer, and then it gets very cold where I live from December through February. I'm not insane enough to run ou

One big reason is the weather. I run outside all summer, and then it gets very cold where I live from December through February. I'm not insane enough to run outside on icy roads, etc. We finally got a trainer for a road bike we can use during the winter, but it's not the same as running outside so I usually get burned out on it.