I've been trying to discipline myself of late to always write my tests first. In a personal project, I found two things: first, I can see the code working right away, and second, I tend to write code in such a way that it's easy to write tests for.

The first is important on code I'm not being paid to write, because I have a tendancy to write all the interesting portions of the code and then stop. I can't tell you how much 3-5 year old code I have in my projects directory that won't even compile because I gave up on it.

The second is really interesting. I often find that the code that is easy to test also happens to compartmentalize into subroutines well, so it ends up encouraging good design anyway. Certainly a case of constructive laziness.

Have other monks that use Test Driven Development found the above to be true?