[goguy]

If you use third party libs with the appropriate licence then your the one that fixes it, just the same as if you rolled your own.

[zajio1am]

If you rolled your own, you invest your time to learn about the problem domain. If you use third party libs, you invest your time to learn about its interface/behavior. That is usually much more ephemeral knowledge. It is good tradeoff if the library does some heavy lifting, but that is not always true.