I give a lot of beauty advice.

Friends and family ask about the latest and greatest products. Readers write in with their burning beauty questions. Colleagues stop me in the hallway.

And I love it! I'm always happy to talk eyeliner or recommend a budge-proof lipstick.

Sometimes, though, my recommendations are not for everyone.

Ask me about eyeliner, and I will tell you about the stila Stay All Day Waterproof Liquid Eye Liner, $22 at Sephora. I will tell you over and over again. But if you happen not to want a liquid eyeliner, my recommendation will not be of much use to you.

But there is one beauty tip that I've given repeatedly, to women of every age, and every single one has found success: Apply your dry shampoo at night.

No, this isn't like the time I told you to put on eyeliner at night. This has nothing to do with getting makeup practice.

These days, lots of us are making our blowouts last longer by going a few days in between shampooing. To add volume to second-day hair, soak up any excess oil, and freshen, we turn to dry shampoo. (There are many good dry shampoos on the market, but my absolute favorite is the Dove Volume and Fullness Dry Shampoo, $3.99 at drugstores.)

But here is where a lot of people go wrong.

They wake up in the morning, perhaps a little later than they ought to if hair-washing is on the agenda. They notice their hair looks a little lackluster. They spray on a boatload of dry shampoo.

And all day, their hair still looks dirty and greasy, but now with the added benefit of a white tint from the product.

Not what we're going for.

No, what we want is volumized, clean-looking hair. And the best way to get that is to be honest with yourself before bed.

You're not going to wake up in time to wash and blow-dry your hair! You're going to hit the snooze button too many times and then run around frantically to get out the door. And that's OK. Because a liberal application of dry shampoo before you slip between the sheets will save you.

Really, apply a lot. Section your hair so you're applying the product only at the roots, and go nuts. Then, don't touch it, and hop in bed. A night of tossing and turning of your head on the pillow will really work the dry shampoo into your hair, and the time (a good eight hours, I hope!) will mean the product will absorb any excess oil you might have had.

You'll wake up in the morning with volumized hair, and no telltale white cast.

Alison Smith will do nearly anything to get a few extra minutes of sleep in the morning. Got a burning beauty question? Email asmith@philly.com.