I think it depends on the venue and the kind of event.
When we were renting venues at the $10k+ level, we needed to pay a 10% deposit and 50% around 30 days before the event.
If we pulled out any time after those dates, we would lose what we pay (I think actually we might’ve had to pay the full 100%) if we pulled out really close to the event.
But smaller venues, might be more flexible. I’d be surprised if any would do a full refund within 30 days however.