If Possible, Buy Instead of Build

Off-the-shelf software may address only some of your feature needs. But consider that building your own software may result in going over budget, being late, and still only addressing only some of your feature needs.

"As a developer, you should reuse as much software as possible. Reuse is 'buying instead of building' on a less grand scale."


Reference:
Brooks, F., "No Silver Bullet: Essence and Accidents of Software Engineering," IEEE Computer, April 1987.