If i create a unit by using trigger, should i set a unit variable for it, or next trigger just use "last created unit" is enough if I wont refer to them in future?
If any unit is created between the time of your first and second trigger going off... well... complications arise.
Example:
Trigger 1 creates a hero.
Trigger 2 adds 1 intelligence every second to that hero. It references (Last created unit).
Trigger 3, which was accidentally neglected, spawns a Footman every 0.5 seconds.
Half of the time, your Footman will be the one who is the "Last created unit" and deny your hero experience not only once, but for every single time. Even if that Footman is removed, your hero isn't technically the last created unit.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.