What do hybrid car batteries really cost?

NEW YORK (CNNMoney.com) -- Question 1: What is the life expectancy of batteries in the hybrids...and how much does it cost to replace them? -Tom

The bottom line is that no one really knows how long they last. Manufacturers like Toyota and Honda have warranties that last for 8 years and between 80,000 and 100,000 miles. But there have been reports, according to Phil Reed of Edmunds.com, that Prius' taxi cabs that are used in Canada have gone 200,000 miles without having to be changed. Now that's pretty impressive.

And since you asked, replacement battery packs for hybrid cars generally cost about $3,000. But remember: the more hybrids that are out on the road, the more likely that there will be more sources and for cheaper batteries and better technology.

Question 2: I have $35,000 in student loans. I've been told you can't deduct student loan interest when your salary reaches some cap. Is that true? -John, Washington DC

Yes, this is true. If you are single, the tax deduction on student loan interest begins to fade out after your adjusted gross income exceeds $50,000. You won't be able to deduct anything if you make more than $65,000. If you're filing jointly, the fade-out begins at $100,000. For more information, go to publication 970 on the IRS website: IRS.gov.

Question 3: When is the right time to ask for a salary raise in your company? -Joshua, California

It's more about how you ask for a raise than when you ask for one. First off, you want to make it all about the company - not you. So make a list of all your accomplishments and contributions. If you've just had a success or finished a project, your case for a raise is strengthened. Before you approach your manager, evaluate his mood and outlook.

Of course, you should make an appointment. When you do present your case, make sure you ask for something a little higher than what you expect to get. Be armed with the typical salaries in your field and how your pay compares. And of course, be flexible. Maybe you can negotiate for Fridays off or extra vacation time.

The real truth about hybrid cars

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