I don't have a set commuting schedule, so I tend to avoid the snow and ice days, which fortunately tend to be rare.
One thing that has stopped me is when I must do something with others that is generally beyond my control. For example, picking my mother up from the hospital a few weeks ago, the bicycle was handy because she drove to the hospital, had surgery, then I met her at the hospital with the Bike Friday, put it in the back of her car, and drove her home.
So far I've avoided riding the 350 mile or so trip between my house and my brother's house, but will probably try it eventually. Probably not going by a straight line, so it could be as much as 1000 miles RT

And, if I do it right, will have a couple hundred miles of ungroomed railroad ballast.
I do a lot of hauling by bike, but I've also not towed a horse in a horse trailer with my bike.