Okay, I have other things to do but I did some math.
So let's say the kid has a lot of other income some how and actually owes taxes. Even crazier let's say he is all the way up in the 22% tax bracket.
He takes $5,000 and invests it in a traditional IRA and saves $1,100 of taxes. He leaves that money in there for 50 years and does well with a 9% rate of return. After 50 years it has grown to $371,788! Then when he takes it out he pays taxes of 22% which is $81,793 leaving him $289,994 net of taxes.
Note that both sides of that are probably wrong, he more than likely is not in the 22% tax bracket now, and more than likely he will be paying more than 22% at retirement but to make the math computation we are assuming the same tax rate on both sides.
If he put that money in a Roth IRA instead he would have to pay that $1,100 of taxes so he would only have $3,900 to put into the Roth. Same thing, leaves the money in there for 50 years and does well with a rate of return of 9%. After 50 years it would grow to... wait for it.... any ideas?? $289,994. The same exact number as the traditional IRA.
The math is the math. If the tax rate is the same then the amount that you have at retirement after tax is going to be the same. That's why people focus on the tax rate side of it.
And for the kid in the original post, I doubt they are in the 22% bracket. More likely 10% or 12% or maybe even 0%. And again, most likely he will be way over the 22% tax bracket at retirement, a kid willing to get a job and work is more likely going to do well in life and might be in a higher bracket because of that and at some point we as a nation are going to have to pay off our debt and that is going to cause tax rates to go up as well.
As a general rule of thumb Roth works great for younger people and not as good for older people. Not because of potential return and time in the market, but because younger people are typically not at their top tax rates yet and older people probably are.
There are instances when you still might want to put money in a Roth even if you are at a high tax rate if you have already maxed out your pre-tax traditional options and still have money to save. The Roth still allows the earnings to grow tax free and if your window of when you need the money is longer than 5 years or so you can save quite a bit that way.