[Qt-interest] How expensive registering a new (custom) event is?

[Mihail Naydenov]

Im looking for advise, should I use as many custom events as I need, or, for example, just one and invent my one "sub-type" (through private enum) of that event.
I imagine registering a new event has some toll on the hole program, but is it noticeable? 
Should I care to limit the num of new events I create and register?
(For now I'm not interested in filtering them)

Thank You
MihailNaydenov