Change Is Inevitable. Here's How to Start Preparing Right Now. Four important words: Work your next job.

One night this past April, Martellus and Michael Bennett were texting each other. If you follow the NFL, you know these brothers: They're big and tough, with Super Bowl rings to prove it. But Martellus also spent the past few years making comic books and other entertainment for kids, and he recently retired to pursue that work full-time. Michael is still in the NFL, but he knows it won't last forever. So over texts, Martellus was giving his brother advice on how to build a bridge out.

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"Posting team photos on your [Instagram] is cool for likes but not for growing your brand outside of the game," Martellus wrote in one message. "Use those things to get 'em there, but sprinkle in your awesomeness outside of football while you have their attention."