Military Aircraft at Local Airport?

I live in a smaller city of about 40 thousand or so, and we have an airport here. I do have a question about military aircraft though. There is a U.S. Army Guard unit here that flies the OH-58D Kiowa Warrior, but other than that no military aircraft are based here. I’m wondering then why we get occasional military visitors. I’m not complaining, as its always nice to see something new, but I just never understood why they would land here. We have T-37’s, T-38’s, and T-1’s from Columbus AFB all the time, and sometimes in addition to their usual touch-and-go pracitce, they will land and stay a night or two. The other day I saw a T-45 out here. I’ve also seen a C-130, CH-53, CH-47, UH-1, UH-60, AH-64, OH-58, AH-1, CH-46, and possibly a C-12. What would be the best reason for these aircraft and helicopters stopping by and staying sometimes a night or two?