Once you do get the system re-inflated, you'd be well advised to find out why it's deflating. Yes, air can leak out of the system over time, but that time should extend to weeks and not days or hours. Last time mine was left for any length of time, it had dropped a small amount, not all the way but it was noticeable after about three weeks.
The usual (and first) place to look is the bags leaking from a pinhole or a crack in a fold. Some will advise you to fully inflate them with the ORM switch and spray them with soapy water, which will work ... sometimes, but not always and if no leak shows up using that method, you can get led up the garden path.
From personal experience, I would advise that as soon the windy springs start playing up you change the bags, first as last, almost as a diagnostic step. If that fixes the problem then no further action is required, if not, then more digging is required, but you won't have to keep going back to suspecting the bags.
When you change the airbags, always change them as a pair. I have heard tales of woe where owners have changed one bag Because "That was the side that dropped" and found themselves in all sorts of trouble trying to diagnose the "problem" which would have been solved if both bags had been changed together.
