Called every frame on the client. Called every tick on the server.
By default, it runs about 5-6 times per second on the server, but you can force it to run at servers tickrate using the example below.
Force the think hook to run at the maximum frequency. This is generally only useable for anim entities, if the entity has any animations.
function ENT:Think() -- Do stuff self:NextThink( CurTime() ) return true end