How Often to Replace Brush Heads, and Whether Third-Party Heads Are Fine

The ADA's guidance is to replace a toothbrush every three to four months, or more often if the bristles are visibly matted or frayed. Most makers here state three months; AquaSonic says its heads last four, and Oclean says two to three for its Ease heads. Several handles remind you: Sonicare's BrushSync, Oral-B's refill alerts, and colour-fading bristles on Oral-B's kids' heads.

Every per-head price below is the maker's lowest per-unit price on a genuine multipack that fits, from its own store. This is the figure the three-year cost is built on.

Non-genuine heads for Oral-B and Sonicare handles are widely sold for a fraction of the maker's price. This site does not list or price them. Three things change when you use one: the head is a different product from the one the maker's specifications and cleaning claims were written about; a handle's ADA Seal listing was earned with the maker's own heads, so it does not extend to someone else's; and some makers' warranty terms exclude damage caused by non-genuine parts, so read your handle's warranty before switching.

Fit is the other practical issue. Sonicare's click-on heads and Oral-B's non-iO round heads each fit a whole range of handles, but Oral-B iO heads fit only iO handles, and quip, BURST, Laifen and Philips One heads each fit only their own family.