I am forever in wellies or my leather walking boots once the weather starts to turn! I always used to have boot bags; but they tend to be messy as the mud gets on the sides; zips and collects in the bottom. Inside the boots get damp as they are then zipped up and left.
I found this under my stairs a few years ago and was repurposed! Unless you have really big feet, one boot fits in neatly each side. They stay upright, you can carry if necessary. The boots can air, and the container can be hosed clean when it gets very muddy!
Fits in the boot of cars, in the footwell behind the front seats etc.
If I need to take out of the van for any reason they just sit in the porch as is!