Plumbing and maintenance
Replacing taps in an older bathroom or kitchen
The short answer
Tap swaps are simple until the old back nuts are corroded and there are no isolators. Access underneath is what decides the job length.
Your questions answered
Do new taps fit old holes?
Usually, but check the hole centres and whether the tap needs one or two holes.
Can any tap go on any system?
No, some taps are unsuitable for low-pressure gravity supplies. Check the minimum pressure rating.
The practical points
Corroded fixings on old pillar taps often need cutting rather than undoing, especially on ceramic basins where force risks cracking the bowl.
Fitting flexible tails and isolators at the same time makes every future change far quicker.
Add replacing taps to a wider project?
Plenty of this work happens alongside other jobs in the house. Tell us the whole picture and the sequencing gets easier.