With regards to claiming tax exemptions on your paycheck. You can claim your actual number of exemptions that you'll file with thereby making your tax withholding as accurate as possible. However, you're not required to do so for your paycheck tax withholding so people approach the topic with varying philosophy.
Some people claim 0 exemptions even though they can claim more. They'll see a lower net amount each paycheck, but will have to pay less at the end of the year (or may get some back). Those who do this claim that it helps them manage their money better by letting them get used to a lifestyle with a lower income. And when the tax return comes, they can save the money or treat it as a nice bonus.
Others claim up to 99 exemptions. They get more per paycheck, but will ultimately have to pay the money back in owed taxes. They do this because at the end you'll end up paying the same amount anyways. If they pay more than they need to up front it's like giving the government an interest free loan.
What's your philosophy on this?