Well, the answer is NO!

Project management is a tool that can increase your level of effectiveness either as an individual or as an organization so you can go ahead and practice it in the best way possible.

That being said, you should at least be trained in the art and science of project management so you have a better understanding of what to do, when to do them and why you are doing them.

We all practice project management in different ways but a good training course will arrange or re-arrange your thought and practice to increase your level of success in implementation.

Second thought. When managing small, in-house, personal, non-complex project, your basic skill may be ok. But when you start being exposed to medium to large scale projects, technical and complex initiatives, you definitely need to get more training and look out for appropriate certification to qualify your experience in handling such projects.

Certification, especially from a recognized body gives credibility to your skills and confidence to your clients/employers.