Event questions?

I would just like to make clarify how the Events work so if the answer is no that’s fine.

Under Prices is “Number of Days” if number of days is set to 30 and I create an event now that will run in December then the event will only be visible for one month from the day I created it.
If I set “Number of Days” to “0” then the event will be there forever?

Or do Events run from the time they are listed until they expire?

Is there a way of making events only visible say 30 days or 3 months before they start?

Thanks