There are tons of ways to get a hold of students. Some are obviously checked more frequently (twitter, Instagram, text, calls) and some not so much (Facebook, email). Its pretty easy to send out a message to get a hold of someone, but the biggest thing is the response. Sure you can send out tons of messages and even get some responses back, but many times they get left out in their inbox without any action.
Even times of personal invitation to come to something, you get mixed responses. We are in the generation of "maybe." Everything is maybe, we'll see, or possibly. Theres a great lacking of reservation or commitment present.
With this said, for both you and your students, multiple requests without attendance gets old. This brings us to the great wisdom I'm writing about. Use your requests wisely. Make sure the thing you are asking your students to come to will be positive, impactful, fun, and full. More events equals less attendance, more work, and lots of awkwardness. Less events (at least right now) equals more attendance, positive feedback, and a fun time.
Another great thing to consider is if this event is worth the invite. Is this an event that will lead them to Christ, or help them follow Jesus? Will it lead to another event that will help them in their walk?
These are the things I tend to forget to ask myself.