I wish I had a more straight forward answer for you, but the truth is that it depends. Being promoted not only has to do will your skills and success at doing lower level roles, but it has a lot to do with the company you work for. Things to consider would be how much opportunity to grow is there. For example, if there is only one lead designer and they aren't planning on going anywhere for a long time, then it will be awhile. It also depends on what that company is looking for in a candidate to promote. I hope this helps.