Here's the thing about the NFL offseason—there really isn't one.
The games may end in February, but for NFL teams the work most assuredly does not. As a matter of fact, the success that teams enjoy (or do not) in October and November depends largely on what they do in March and April, whether it's successfully navigating free agency or making good use of draft capital in Las Vegas.
With that said, while every team has work to do in the offseason, the items on the list in need of being checked off can vary widely from team to team.