Folks have already said most of what I want to say, but I'll chip in anyway.
Through out my years in this game, I must have wasted thousands of pounds on PCB re-spins caused by library components that are wrong. From incorrect connections (like a base/collector swap on a transistor footprint) to pad/paste/resist clearances on IC's that prevent paste release or correct soldering in production. It really seems that the libraries are an inconvenience given to interns.
I do use simple components, resistors capacitors and the like, but almost all significant parts are created by myself.
As others have said, regardless of the CAD package used if you are going to design PCB's learning to create your own symbols and footprints is a must.