Both quartz and porcelain are non-porous, which means caring for them is genuinely simple.
Most of what people worry about is unnecessary, and most of the damage we see comes from products sold as “stone care” that these surfaces do not need.
Everyday cleaning
A soft cloth and warm water. Mild dish soap if you want it. That is the whole routine.
What not to use
No sealers, penetrants or topical treatments. These surfaces are non-porous. There is nothing for a sealer to soak into, so it sits on the surface and hazes.
No abrasive powders or scouring pads. They will dull a polished finish.
No bleach, oven cleaner or drain cleaner. Wipe up immediately if any reaches the surface.
No cutting directly on the stone. It will not scratch easily, but it will blunt your knives.
Heat
This is the one real difference between the two materials.
Quartz: always use a trivet. A pan straight off the burner can scorch it or cause a hairline crack from thermal shock. This is the most common damage we see and it is entirely preventable.
Porcelain: heat-resistant. Set the pan down.
Common questions
Something stained it — what now?
Almost certainly it has not stained; something has dried on top. Warm water and a plastic scraper, then mild soap.
Can I get a scorch mark out of quartz?
Sometimes, with a non-abrasive polish, if it is light. A deep burn is permanent.
Do I need to reseal it, ever?
No. Not after a year, not after ten.
Hard water marks?
Common in parts of southwestern Ontario. A 50/50 white vinegar and water solution, left a minute, then rinsed. Do not leave vinegar sitting on the surface.