So if there is a bug which appears to 1 in 1000 users, with no impact on their ability to get their work done, and which would take two weeks to fix, you’d stop everything and fix it? Or not, and since you have no bug tracking software, have no way to record it? Also, with no bug tracking system, until you arrive at your mythical bug free state, on what basis can you analyze the frequency and severity of your bugs?