Nearly all taps you buy today have ceramic cartridges inside that control the water flow through them. Only older taps tend to have the rubber washers. These older style taps can be easily repaired in most cases by gently re-seating the tap and then renewing the washer. Ceramic cartridges if they start to drip, will in most cases require the cartridge to be renewed. There are hundreds of different types of cartridge on the market so tip for the day: Make a note of where you purchased the taps and what make and model they are. Sourcing the cartridge is easier and means they’re repairable. Don’t make a note of where purchased/make/model etc and the dripping tap suddenly becomes a set of new taps required at larger expense.