Investing in that vacuum is a big expense

(Consumer Reports) - A vacuum cleaner is a big purchase - and when it's time for a new one you're going to be faced with a lot of choices in the store.

If you're looking at upright models, you'll have to pick between bagged or bagless - those clear bins that collect all the dirt.

Consumer Reports has tested vacuums over thousands of miles of carpeting to see which are the best.

Valerie Cordoba uses her bagless vacuum twice a week, to clean up after her two young children and a shedding dog. Seeing the dirt in the bin makes her clean it more often.

"I empty the canister immediately because I just don't like to have the dirt there. I need to get it out of sight," Cordoba said.

Which should you go for, bagged or bagless? Consumer Reports tests both types vigorously - to see how well they pick up dirt and debris, how easy they are to maneuver and how they perform on different types of flooring.

The perception is that bagless are easier to maintain - and with no bags to replace, they're cheaper to own, right?

Well, bagless machines actually have more filters to clean and replace than bagged models. And to keep it running its best, the bin and surrounding parts should be cleaned from time to time.

You are apt to empty it more often, because the dirt is visible in the canister. But there is a drawback.

"Emptying these dirt bins can be messy, because when you open them up, you're releasing some of the particles back into the air that you just sucked up,” Sue Booth of Consumer Reports said. “And that's something to take into consideration if you have allergies or dust sensitivity."

Vacuums that rely on one, big main filter - the bag that collects the dirt - might be the best bet for people with dust sensitivities. Some bags can even be sealed when you remove them - with sliding closures or stickers.

Bagged models also have HEPA filters to clean, although they don't need to be changed as often since dirt goes directly to the bag.

And whatever style you choose, bagged or bagless, the suction should stay the same no matter how full the container is.

"This is our tool air flow test. We measure the suction when the bag or the bin is empty. Then we add wood flour to see if the suction performance changes," Booth explained.

CR found this Shark bagless model does well cleaning carpets and excels on bare floors.

CR also recommends this bagged Kenmore. It does its best on bare floors, and does an excellent job picking up pet hair.

Consumer Reports says that if your old vacuum can make it to the holidays, retailers will be battling for your business, so take advantage and save.