Just went through this with Flair (the sofa bed manufacturer).
We have an "original" model air mattress (it did not come with a storage bag and had a "flocked" top surface. The replacement model is smooth both sides and comes in a storage bag that Velcros to the back frame.
I got a pinhole in the mattress when the mattress got pinched putting it away. We discovered this the first time we used it and it slowly deflated in the middle of the night.
I used a bicycle tire repair kit to fix the pinhole and it worked great.
The next time we tried to use it it deflated slowly again. Unable to find the leak, I called Flair; and even though it was out of warranty, they sold me a replacement queen size mattress at a "good will" cost of 75 dollars shipped. Since it was the new model, it came with the storage bag and the sealed in 120 VAC pump just like the original. 75 bucks was a great deal on a queen airbed that is MUCH more comfortable that the queen sized Aerobed we also have.
I have since found that there is a yellow tab in the quick deflation port at the front that can partially open if someone sits on it. Since the cap was not completely sealed it slowly deflated. THAT was why I could not find the leak in the material.
We also own a battery powered Aerobed twin for the dinette that is very comfortable but due to poor design can roll you out of bed if you get too close to the edge.
I should have taken the opportunity to buy the "good will" priced twin mattress while I had them on the phone.