After changing the mobile phone, the traffic is particularly large. How do you usually prevent insufficient traffic?

My previous method was to play where there was WIFI as much as possible, but I found it impossible to have WIFI all day. Later, I learned from my classmates and downloaded a traffic. I won't say that it's so easy to lack traffic when playing, and it just recently updated version 2. 1, adding a lot of functions and traffic activities. So this method has been used to prevent insufficient traffic.