I started out my woodworking career with a quarter-sheet electric sander, quickly graduated to a random orbit electric disc sander and finally realized that I could substantially shorten sanding time with an air palm sander. I settled on a 5" Dynabrade sander and Sears 3HP air compressor. It took me less than an hour to realize my mistake: The little compressor I bought could not begin to keep up air demands of the air sander. It would run out of air pressure almost immediately and the air sander would slow down to the point of being useless. I would then have to wait for several minutes for the pressure to build up again to get another minute of sanding.
To make matters worse, I had three people hired as sanders and so I would need to keep three machines running at top speed all day long. I did some math and discovered that I would need a ten horsepower air compressor with a large tank to do this. I was lucky to find a used one for not too much money but it required three phase power and lots of it. More money went out for an electrician to wire it up to the building's 208 volt 3-phase power. The big air compressor was so loud it could be heard all over the building and down the block but it powered those three sanders from dawn to dusk. The good news is that it paid for itself in saved sanding time very quickly.
Air sanders are aggressive and efficient. They are light in weight when compared to their lesser electric cousins. My sanders took to them immediately and production took off. I was as happy as they were. Soon there was another machine besides the air compressor required having large amounts of air in the shop: an Onsrud inverted pin router. It was also great to be able to blow sawdust of benches and machine while cleaning upon the shop at the end of the day. The compressor was also used to spray finishes on the completed furniture.