There actually are legitimate reasons, but they don't apply to most people.
Here are a few that I know of: You're self-employed and have to pay quarterly estimated taxes.
Rather than wait for the refund when you already have to pay 1/4 of next year's taxes at the same time, you just have the IRS apply to refund forward.
(so you're not out the money you owe while waiting for your refund).
You're filing an amended or late return, and so you're already into the next year, and have a similar situation as #1, where your next year's taxes have already come due.
You're planning on declaring bankruptcy, and you're under the Tenth Circuit,
those credits might be safe from creditors For almost any other situation, you're better off taking the money, and using it to pay down debt, or put it somewhere to make interest (although, at the current rates, that might not be very much).
money.stackexchange.com/users/9800/Joe
Aside from the fear that you or a loved one will spend it frivolously, I'm hard pressed to come up with another reason.
If you'll owe money in the next tax year, you have the rest of the year to adjust your withholdings and/or make quarterly payments.
As both my fellow PFers state, you're better off getting your money back.
Better still, use it to pay off a high interest debt.
money.stackexchange.com/users/187/JTP - Apologise to Monica
If your refunds are subject to seizure because of certain debt arrears, it makes sense to let the IRS hold onto them until next year.
money.stackexchange.com/users/25501/J. Win.
It is a bad deal.
It saves the government from processing your refund as a check or an ACH deposit, and lets them keep your money -- money that they overwithheld! -- interest-free for another year.
Get it back. :)
money.stackexchange.com/users/414/mbhunter
If you expect your taxes to be higher next year, it saves you the trouble of sending estimates or changing the withholding levels.
But yes, its basically a free loan you're giving to the government.
money.stackexchange.com/users/2998/littleadv
If you have non-salary income, you might be required to file 1040ES estimated tax for the next year on a quarterly basis.
You can instead pay some or all in advance from your previous year's refund.
In theory, you lose the interest you might have made by holding that money for a few months.
In practice it might be worth it to avoid needing to send forms and checks every quarter.
For instance if you had a $1000 estimated tax requirement and the alternative was to get 1% taxable savings account interest for six months, you'd make about $3 from holding it for the year.
I would choose to just pay in advance.
If you had a very large estimation, or you could pay off a high-rate debt and get a different effective rate of return, the tradeoff may be different.
money.stackexchange.com/users/1992/poolie
The refund may offset your liability for the next year, especially if you are a Schedule "C" filer.
By having your refund applied to the coming year's taxes you are building a 'protection' against a potentially high liability if you were planning to sell a building that was a commercial building and would have Capital Gains.
Or you sold stock at a profit that would also put you in the Capital Gain area.
You won a large sum in a lottery, the refund could cushion a bit of the tax.
In short, if you think you will have a tax liability in the current year then on the tax return you are filing for the year that just past, it may be to your benefit to apply the refund.
If you owe money from a prior year, the refund will not be sent to you so you will not be able to roll it forward.
One specific example is you did qualify in the prior year for the ACA.
If in the year you are currently in-
before you file your taxes-- you realize that you will have to pay at the end of the current year, then assigning your refund will pay part or all of the liability.
Keep in mind that the 'tax' imposed due to ACA is only collected from your refunds.
If you keep having a liability to pay or have no refunds due to you, the liability is not collected from you.
money.stackexchange.com/users/47060/cameosun
If your refund is so small (like $20 - $25), and it's not worth receiving, it can be put towards next years just to give you a slight edge.
money.stackexchange.com/users/41585/Steve
Not a financially sound decision in my humble opinion.
Basically, you are prepaying your taxes and the only reason you want to do that is if you don't have the discipine to save that money for when it is time to pay next year (assuming you will have to).
money.stackexchange.com/users/39396/JStorage
i filed a chapter 13 and as part of the settlement with bankruptcy trustee i must give them a copy of my 1040 and any tax refunds.
I may use the carryover rule to get around losing money.
money.stackexchange.com/users/67375/user67375
Every year I get a refund and the tax software asks me if I'd like to apply some of my refund to next year's taxes.  Is there some benefit I'm not seeing to this?  Because it looks like a bad deal to me.
Why would you elect to apply a refund to next year's tax bill?
money.stackexchange.com
<united-states><taxes>
money.stackexchange.com/questions/12698
money.stackexchange.com/users/2410/jldugger
It saves you from having to keep the money aside to pay your taxes next year. Otherwise, it just lets them keep your money, interest free, for another year. If you end up owing money in the next tax year, you will have the rest of the year to adjust your withholdings and/or make quarterly payments. By having your refund applied to the coming year's taxes you are building a 'protection' against a potentially high liability if you were planning to sell a building that was a commercial building and would have Capital Gains for example. It would also be advantageous if you were planning on declaring bankruptcy. It also saves the government from processing your refund as a check or an ACH deposit, and lets them keep your money interest-free for another year.  Basically, you are prepaying your taxes and the only reason you want to do that is if you don't have the discipline to save that money for when it is time to pay next year (assuming you will have to). 
If you end up owing money in the next tax year, you will have the rest of the year to adjust your withholdings and/or make quarterly payments. S5: You're planning on declaring bankruptcy, and you're under the Tenth Circuit,   S1: It saves the government from processing your refund as a check or an ACH deposit, and lets them keep your money -- money that they overwithheld! -- interest-free for another year.   S0: If you expect your taxes to be higher next year, it saves you the trouble of sending estimates or changing the withholding levels. Basically, you are prepaying your taxes and the only reason you want to do that is if you don't have the discipline to save that money for when it is time to pay next year (assuming you will have to). Also if you have non-salary income, you might be required to file 1040ES estimated tax for the next year on a quarterly basis. So if you think you will have a tax liability in the current year then on the tax return you are filing for the year that has just ended, it may be to your benefit to apply the refund.    S1: By having your refund applied to the coming year's taxes you are building a 'protection' against a potentially high liability if you were planning to sell a building that was a commercial building and would have Capital Gains.