How long for an Author to learn to start making good book covers?

In general, to make covers as good as a Professional Cover Designer, you would need to have a similar level of practice and experience and skill as one That means 3 to 4 years of College to learn Graphic Design 5 to 10 years of working as a Graphic Designer doing 5 to 8 hours of design work each week day 5 to 10 years of working as a Book Cover Designer, doing 5 to 8 hours of book cover design...