DUB is not set up for early baggage acceptance. Under three hours (maybe 4) is fine, but dropping bags earlier than that would be an exception.

If you're Gold or above, and the check-in desk is not busy and feeling benevolent, they may call the baggage hall to ask if they have space. I would go armed with some charm but expecting nothing, as DUB is not really equipped for it, and when they say there isn't space in the baggage hall, they mean it.

I've had success with one bag, but large groups may have different experiences.