I'd say try to plan for how much you will need to scale your code, and also how many others will be working on your code. As your code gets larger, and as you

I'd say try to plan for how much you will need to scale your code, and also how many others will be working on your code. As your code gets larger, and as you start to have others working on it (who could break it), unit tests become more important. If you dont foresee either of these happening, then the time investment for tests may not be worth it..