I've got a friend who wants to upgrade his compressor but doesn't have a lot of space for a large 60-80 gallon tank. So far he's been using a little portable compressor which works fine for nailers, etc but he wants to get into sprayed finishes and we all know that once you have a new toy, you're going to find uses for it and air tools are probably in the pipe somewhere down the line.
What would everyone say is the minimum tank size for moderate use of relatively high capacity air-using tools like sprayers and perhaps air sanders? I doubt he'll be using it every day or even for long when he does, but I don't want to recommend something and have him run out of air in the middle of a job either.