I don't care if it's 28, 25 or 23, how often do you use that bailout gear? While you're thinking about how you will respond, I'll answer my own question. I have a 11-28 cassette, which I bought specifically because where I live I'm surrounded by little else but hills, many of them long and steep. I'm not talking Alpe d'Huez long and steep, but challenging nonetheless. Because of where I mostly ride, I have gotten myself into physical shape to where I don't have to use the lowest gears anymore.

My favorite gear for climbing most of the moderate challenging grades near me is the 34x22. I know my limits however, and won't hesitate to drop it down to the 25 or even the 28. After long rides especially, and with any headwind on a final climb, I can't find the 28 fast enough. On a recent long and tough climb (over 7K of elevation, much of it at least 6%), I took note of the gearing everyone used. Almost everyone -- no matter the bike frame material (the vast majority were on crabon), or the size and sheen of their guads and galves -- was rocking the bailout gear. Including yours truly.

Do I want an even lower gear? Honestly, no. If I can't climb using the 28, then I have no business on that ride. That's just me. To answer: I probably use the 28 just a few times a month. Maybe once a week.