In the US the networks try to refrain from calling states early. Though when you see early voting numbers already being release, all the freaking poll data we get bombarded with, etc You wonder what is the point. But there are down ballot effects, if networks call enough states early then people further west start thinking why bother voting, which may not change the national races, but might affect the local ones.
The reality is though as results start coming in, the networks share them, even if they don't officially "call a state"
It really is no big deal to wait until later.