The only time you can spend a token is when an effect allows you to do so. You can not spend it on nothing,
Where in the Rules/FAQ is this stated?
The rules include effects that allow you to spend tokens. It doesn't mention allowing you to arbitrarily spend or discard tokens.
Spending a token to reroll zero dice or to change zero eyeballs to hits is still spending a token to perform their default modification effect.
If Palob moves into range 1-2 of a ship that has a focus token is it kosher for the player controlling that ship to announce "I'm going to spend my focus token" and remove the token from play before Palob has a chance to steal it? The rules don't say that you can't do that so it must be okay, right?
Edited by WWHSD