There are a different "types" of triggers. Which one(s) you use will depend on when you want the trigger to run and what information you want to check conditions against.
The four universal trigger types are as follows:
As the title indicates, this trigger type will evaluate the set conditions every time a player joins.
This trigger type will update only when player information is updated or changes. The events that can lead to a player update are changes to score, ping, or a Steam API update, which happens at a fixed interval.
Note: The Steam API updates are checked every five seconds, but can be delayed up to five minutes. The Steam API calls depend on the availability of the Steam API. A Steam API update typically takes fewer than 15 seconds to complete.
This is the recommended trigger type for any conditions that are dependent on Steam information, such as VAC ban status, profile status, etc.
This trigger type evaluates its conditions each time a player leaves the server.
This trigger type evaluates its conditions any time there is an update to the server, including players joining the server, leaving the server, the map changing, etc.
While there are other types of triggers, there are simply too many to list and each is dependent on the game and server you are running the trigger on. Please read the description of the type you are choosing to learn more about what it does and when it evaluates its conditions.