Quite often we see paving stones that are badly delaminated like this driveway we recently replaced. Bricks delamination occur when the bricks surface chip, frail, crack and dislodge prematurely from normal wear and tear of every day driving and walking on them.
Usually these bricks are factory rejects and should never be used. Unfortunately, some contractors install them as a cost effective way to increase their margin. When you consider hiring a paving stone contractor, make sure you ask what type of pavers they would be installing. If it is factory seconds or rejects, avoid using them no matter how low cost it may sound.
Cheap bricks don't last and replacing them within 5 - 10 years will cost you more than the savings you wanted to see in the first place. At first, you may not be able to tell bricks' quality so it is important to learn about the stones and bricks your contractor will be using before your project begins.