Waterstop is a good suede protector which is tested well for furniture protection. It is an aerosol spray and will go a long way on boots, but it does need to be applied fairly regularly.
You can buy waterproofing spray that will prevent your boots from getting ruined by bad weather. Two coats will give good coverage. You should be able to find such products in a supermarket.
Unprotected suede should not be worn in the snow or slush. If it were just plain snow, it wouldn't be a big issue, but the salt and de-icers used on sidewalks and streets is the bigger problem. The salty water will severely damage the suede and it wi...