To fire an event when a value has changed, you have to know the old value, and check to see if it has changed.
To simplify doing this over and over I have a macro that I use to track if a value has changed.
This macro saves the setup value. Then every time you call the check, it will fire wither Value Not Changed or Value Changed, if Value has changed, you can look at the Old Value and New Value parameters.
To use this, I recommend calling the Setup on BeginPlay, and call Check Change on Tick. Here is an example I have setup. With this setup, no matter who changes the score, the next tick will detect the change and fire off the Print String. In my normal case, it would be calling an EventDispatcher with the value change parameters.
Here is what is seen in the console, when I update the score a couple times.
