The NIH (Not-Invented-Here syndrome) is probably well-known, but this blog post puts focus on the less-known other side of the coin: the Invented Here Syndrome:
It agrees quite well with my experience from development in several companies. In a well-meaning effort to meet increasingly tight deadlines and demands to the software to be delivered managers and even quite a few programmers fall prey to the idea, that time spent writing code is wasted, if some third-party software exists that does roughly the same thing.
This however ignores time spent researching suitable third-party software, learning how to use them, working around bugs, head-scratching due to lack of documentation, writing wrappers around not-quite fitting designs and increased complexity of the solution in general.
This does not mean that every piece of software should start from scratch, but keeping in mind that using third-party software may carry quite a few hidden costs may help us make better choices when considering "Download" or "Build"?