> For non-tech people the code should be a black box they shouldn't know the internal details. Ideally, yes, though in practice this usually breaks in various

> For non-tech people the code should be a black box they shouldn't know the internal details. Ideally, yes, though in practice this usually breaks in various ways, especially when problems occur. E.g. the President of a country probably doesn't need to be a firefighter, but if there's suddenly a massive fire, I assume he'd need to be briefed in far more detail to help call shots around the type of response. > In terms of refactoring there is no way to give a Cost Benefit analysis as that's too subjective. I mean, you probably won't get a very correct Cost Benefit analysis, but you have to do something. The rest of your post is you describing that something - if you elect to spend 20% of your time on maintenance, that's effectively giving it a certain amount of weight compared to other things you can be doing with your time. That's certainly one way to work. Personally, I think a more flexible approach is better. E.g. new startup-ish projects should usually spend a lot less time refactoring, for multiple reasons, whereas more established long-term projects should spend much closer to 20%, or maybe more.