contact groups

I have been using gmail with my school account for several years now but have never taken the time to set up each of my classes as contact groups. I now plan to set these up in order to send group emails as well as to use the contact groups to share google docs and slides projects- two other google tools that I frequently use with classroom projects and notifications. The "old system" of "manually" entering kids names - which was also quite quick, had the weakness of sometimes missing a student. While it takes a little while to set the contact group up, I'm sure that it will pay off in the long run as I share many emails and projects through google apps.