So when I was in the hospital and my poor lungs were being crushed by fluid, I had a little breathing do-jiggy that I was supposed to use 10 times an hour (in any number of sets and reps I wanted). I put it in my mouth, took a deep breath, and measured where the little arrow went up to. I call it my suck-meter: an objective measure of how much I really suck.
In any case, I couldn't do it much a while ago. I brought it home and used it a lot when I first got here, monitoring progress. Then I had some pains in my side and couldn't take a deep breath. Then I tried it again the other day, and I came close to maxing it out. I think the lungs are clear :) Which, ironically, means I really suck.