Do white porcelain slabs discolour or turn yellow over time?

No, white porcelain slabs won’t turn yellow or fade over time. Porcelain doesn’t absorb water or dirt, so things that usually cause yellowing or stains can’t easily soak in. Even after years outside, your white paving will keep its original bright colour. The only thing you need to do is clean the slabs regularly to remove surface dirt and keep them looking fresh.