To be successful in most endeavors, it’s important to develop good habits — and that’s certainly the case for investors. And the earlier one develops these habits, the better. So, if you have teenagers who may be starting to work at part-time jobs, now may be a great time to introduce them to investing — and one place to begin might be a Roth IRA.As you may know, a Roth IRA is a popular retirement savings vehicle — its earnings can grow federally taxfree, provided withdrawals aren’t taken until the investor is at least 59½ and has had the account ...