On pavement the studs are not as good as without them. They are slow and noisy. Many types of ice can be ridden on without studs. Every once in a while there is ice that is not possible without studs. The weather varies so much it's hard to know what is going to happen. No way really to find out how much you will use them. The studs do wear on pavement. Tungsten carbide studs will last 4 or 5 times longer than steel on pavement. Some riders will wear out a set of steel studs in one year. Some tires have easily replaceable studs. In snow and slush unless there is hard pack snow or ice underneath for the studs to grab they don't make much difference.
I gotta tell ya I can go straight over 2" deep footprints frozen in ice as fast as I want with studded mtb tires. I have almost as much traction on the ice rink as pavement. It is a lot of fun! Are there any lakes nearby?
