97 Things Every Programmer Should Know

Chapter 72. Reinvent the Wheel Often

Jason P. Sage

Just use something that exists—it’s silly to reinvent the wheel.…

HAVE YOU EVER HEARD THIS OR SOME VARIATION THEREOF? Sure you have! Every developer and student probably hears comments like this frequently. Why, though? Why is reinventing the wheel so frowned upon? Because, more often than not, existing code is working code. It has already gone through some sort of quality control and rigorous testing, and is being used successfully. Additionally, the time and effort invested in reinvention are unlikely to pay off as well as using an existing product or codebase. Should you bother reinventing the wheel? Why? When?

Perhaps you have seen publications about patterns in software development, or books on software design. These books can be sleepers, regardless of how wonderful the information contained in them is. The same way that watching a movie about sailing is very different from going sailing, so too is using existing code versus designing your own software from the ground up, testing it, breaking it, repairing it, and improving it along the way.

Reinventing the wheel is not just an exercise in where to place code constructs: it is about how to get an intimate knowledge of the inner workings of various components that already exist. Do you know how memory managers work? Virtual paging? Could you implement these yourself? How ...