Well it's actually quite simple - the amount of bugs depends on the amount of code - less code, less bugs. To truly eliminate bugs, you either need to be able

Well it's actually quite simple - the amount of bugs depends on the amount of code - less code, less bugs. To truly eliminate bugs, you either need to be able to see the future or have learned from your mistakes and from others' mistakes. (The latter being more common) Depending on what you're doing, chances are if there isn't a clear separation of concerns and you're not following good/best practices (ia. solid, grasp, design patterns, ddd/tdd/bdd/*design) and - proper planning - there will be bugs. Another thing developers generally struggle with is calling something by its name, ex. var a = 13 vs. var age = 13. That generally confuses even the developer himself after he went to take a leak. I also agree on all Samikcs points - in addition to that there is really a lot of different ways to 'test code' ea, integration testing, unit testing, behavioral testing, requirements testing, deployment testing etc. - even software testers have to attend courses/study. If you've read up to here, you will have realised there is no one answer. Programming isn't a task to be taken light-heartedly. Plan. Develop. Test. Verify. Repeat.