Pretty much never. They do not cover soccer which is what I watch a lot. And for baseball I just watch the highlights from MLB.com website. They have most homeruns hit which is what I care most about.
Some nights when we have an 8 ball, we will watch like 9 hours straight of NHL on the fly, which is the days hockey highlights repeated over and over and over again....
Zero. Sports center sucks. If an event means that much to me I'm gonna watch it live. Now when I was a kid I'd watch SportsCenter over and over and over.