I think one good threshold for most startups is product-market fit. Before you have it, you should be willing to accumulate large amounts of tech debt both bec

I think one good threshold for most startups is product-market fit. Before you have it, you should be willing to accumulate large amounts of tech debt both because your product might change enough that you'd be rapidly throwing out large amounts of code anyways and because having product-market fit is such an overwhelming need that almost everything should be traded against it because your startup is dead without it. After you have it, you have to be much more diligent about paying down tech debt, because you switch from a more "exploratory" mode to a "refinement" mode where you now are unlikely to be throwing away large swaths of your code at the drop of a hat, and instead need to iteratively build upon what you already have and that becomes very difficult to do with large amounts of tech debt.