I polish my boots at the start of every shift and often during the shift if they need it.
There is a brush and polish in my duty bag, there's another kit on the bench in my garage at home and the department puts them in the locker rooms as well.
It's one of my little OCD traits. Most likely comes from the punishment I got once in the Army for having dirty boots.
The shoes I wear to court are spit polished, but the boots are just done with a brush.