16. You Always Pick Up When They Call
Always. What if that guy forgot her number and she needs consoling? What if she's been set on fire and you're literally the only person who could possibly douse her? If you don't speak to each other for two days, it'll take you around two months to have a full catch up. Constant communication is essential, especially in the form of Snapchats so you can at least see her face no matter what the distance between you.