Investing in an exchange-traded fund can be an easy way to grow your wealth in the long run.You don't need to be a great stock picker to generate strong returns from your investments. In a lot of cases, all you really need is to find a good exchange-traded fund (ETF), or perhaps a few of them, and to have a great deal of discipline. Finding some strong ETFs to put your money into and having the discipline to leave it alone and remain invested for not only years but decades can set you up for significant lon ...