First, how long you study by yourself is a subjective factor, and personal initiative also has a great influence. Second, automotive sheet metal's technology is complex and changeable. The damaged parts of each car are different. How long you study has a lot to do with the business of your four S shop or repair shop. If the business there is good, then we can learn quickly. Sheet metal technology is a technology that practice makes perfect. Do more, do more, practice more. Third: Every time you learn something, you must learn from the master. Then, how long we can learn and what skills we can learn also have a certain relationship with the master. Personally, I think it will take about two years to learn automotive sheet metal technology, if you can do it yourself regardless of the size of the accident car. I hope this answer is useful to you.