Most vacuums come with basic tools (pictured above) that should suffice for most cleaning jobs: A narrow tool for crevices, a small upholstery brush, and a round brush for dusting. On canister vacuums, a powered intake cleans carpets more thoroughly than a simple suction intake. Edge cleaners are an optional tool and can pick up debris under the entire area of the cleaning head. That's useful when cleaning wall-to-wall carpeting; the vacuum cleans right up to where the carpet meets the wall.

Some upright vacuums and canisters use bags; some collect dirt in a bin. Bagged-type vacuums tend to hold more dirt, and emptying them releases less dust into the air. An indicator tells you when the bag or bin is full. With bagless vacuums you can save money by not having to buy bags, but these use more filters (such as HEPA filters) that need to be periodically cleaned or replaced. Replacement filters tend to be significantly more expensive than bags. Another caveat: Emptying the dustbin and cleaning a filter can be messy, and handling them can expose you to dust and other allergens.
 

These include equipment and features that help when cleaning hardwood, vinyl, and other uncarpeted floor surfaces. Most common are an on/off switch for the vacuum's brush; other options include a bare-floor setting.
 

Also known as the roller brush, it is found underneath the machine. This roller has bristles attached to it and spans the width of the base. It dislodges dirt, dust, and grit from the carpet so that the intake can pick it up more easily. Some models have a switch to turn the roller brush off for cleaning bare floors; a rotating brush on a bare floor can move dirt and debris around before it can be sucked up. The switch also makes it less likely for throw rugs, bedspreads, and the like to become tangled in the roller.

This feature adjusts the height of the machine's brush roll to a carpet's pile height to allow for easy movement and thorough cleaning. Adjustments are automatic on some models, but manual control is more precise. A switch for suction control lets you reduce the flow of air through the hose, which can be helpful when cleaning upholstery and curtains.

A growing number of vacuums claim to filter the fine particles that could pass through the machine and escape into the air through the exhaust. Micron filters can provide a higher level of filtration than standard models either through the bag or a separate filter, but possibly not as high as high-efficiency particulate-air (HEPA) filtration. HEPA filtration might benefit someone with asthma. In our tests, models with a HEPA filter have been very effective at reducing emissions. Some models that don't have HEPA filters, however, have performed just as well in our tests, and such vacuums may cost less.  

More common in canisters, it lets you rewind the cord with a slight tug or the push of a button. Most machines have an electrical cord of at least 20 feet; some cords are longer than 30 feet. A cord-release clip, found mostly on upright models, lets you free the entire cord at once, rather than one wrap at a time.

This feature typically uses a transmission and drive system to assist the pushing and pulling of the vacuum, thereby requiring little effort by the user. The downside: It adds weight that can make some vacuums difficult to carry.