Can you file your taxes every 2 years if you're single?

You can... but its a no win situation. If you don't file, and you are owed money, the government gets an interest free loan.

If you owe money, they slap you with penalties and interest on the money that they were supposed to bring in.

So, I wouldn't recommend it.

Also, simply, you must file every year. And adding two years together will virtually always come to a much higher tax (you only get the deductions and evwen withholding credit for one year, not both). many other reasons.