Don't Get Skunked
Testing new code is relatively easy and incredibly important. Unfortunately, many programmers don't think testing is fun, so they do a skimpy job or skip it entirely. Despite the fact that they have never written a 10-line routine without a bug in the past, they somehow convince themselves that the new code is perfect.
NOTE
Glenn, a good friend of mine, recently finished a project where the development team used an interesting strategy to encourage developers to test their code. If you checked in code that broke the system build, you got a rubber chicken tacked beside your door. You kept the chicken until the next time a developer got careless and broke the build.
I'm sure outsiders who walk past these offices and see a rubber chicken tacked to the wall write the experience off as just another of those weird programmer things. Actually it's a way to use peer pressure to persuade developers to test their code. It's more fun and probably more effective than progress reviews and management harangues.
At the end of that project, the chicken retired and Glenn, who happened to be its last recipient, got to keep it. Knowing Glenn, I half suspect he made the last error on purpose so he could keep the chicken.
Now a new project is starting. Instead of a chicken, its mascot is a skunk.
A few minutes testing can save you and others hour of debugging.