Manual testing and design patterns that isolate the effects of a change from the rest of the system.

I am going to manually test things anyways, so in practice, unit testing usually takes longer.

I am more likely to add robusts tests to parts of the code that are harder to test manually as it does save time in that instance.

Ironically, I find that well tested code gives me less incentive to refactor it. Refactoring is good for allowing future changes without breaking things. With good testing, I rely on tests to provide those guardrails instead of a clean code structure.