[drog]

Smaller programs are easier to understand and often you can be sure that they are correct just by looking at them.

Macros allows you to decompose and simplify problems in a way that is impossible with functions. Macros are especially good at removing boilerplate and writing syntactic glue code.

Since macros are programs making sure that they do what you meant them to do you can use similar techniques as you use for other programs: making them small and obvious, testing.