This is why I prefer to turn the problem on its head and ask the business how much time they want me to spend working on 'quality' (i.e. refactoring/tooling).

This is why I prefer to turn the problem on its head and ask the business how much time they want me to spend working on 'quality' (i.e. refactoring/tooling). If it's on a spreadsheet that their boss can see saying that they asked me to spend 0% of my time on quality then I'm ok with it. If they can justify putting that zero down then presumably there IS a good reason. If they're going to put me under implicit pressure to deliver as many features as possible and then cry havoc later when they get bugs then I'll lack sympathy. Product managers are often resistant to the idea of tracking this number, however, since it provides a new angle through which they can receive flak from above.