Divide-and-conquer approaches are very effective in debugging. When you are debugging, you don't break down the problem before starting the process; breaking it

Divide-and-conquer approaches are very effective in debugging. When you are debugging, you don't break down the problem before starting the process; breaking it down is the process. With debugging, you have a concrete implementation and a specific problem to work with. In development, you have to try to anticipate every problem, and coming up with a concrete implementation is the goal, not a given. These complications, IMHO, make design ultimately harder than debugging. If your progress on something is dependent on a mental image that collapses with the slightest interruption, then you are working at the limits of your ability. To go beyond that, you need to be able to record what you know so that you are not limited by your mental working storage. I am interrupted by sleep every day, and the first thing I do the following morning is to review any notes I made on the previous day. Interruptions are certainly disruptive, but your claim that these techniques will not mitigate the problem does not mesh with my experience.