One thing that often distinguishes mysteries from suspense novels is that most mysteries are part of a continuing series. Suspense novels are usually stand-alones.
Many readers of mysteries (myself included) enjoy following these series. You get to know the main characters, their family, friends, and co-workers and how their lives and careers change over time. As soon as you finish the newest title, you look forward to the next book, especially if the latest one ends in a cliff-hanger.