Back in 2003 when I moved to clip less. I ummd and ahhhhd over the cost of a pair of winter boots. But they've repaid the cost multiple times on winter commutes. They also allowed me to go out on the muddiest of mountain bike rides, but still have a clean pair (my summer ones) for the road. I don't mountain bike now (road bike on Bridleways / towpaths don't count) but still have a pair of winter boots. At the moment Shimano something or other (my second pair in 16 years), my first ones were Gaerne which I think were better but reached end of life a few years back. . They are a size larger than my summer ones so I can wear hiking socks under them on really cold days.
The other thing about winter boots is you can just hose them down to clean after a muddy ride. I usually do this whilst still wearing them. I wouldn't dare do that with my summer cycling shoes.
