The Ministry of Business Innovation and Employment(MBIE) released in 2015 a”Guide to building tolerances.” There are some key points for tiling(section 8, page 50)

2015 MBIE Guide-to-tolerances

The normal viewing position distance for tiling is ≥ 2 m (see Inspecting surfaces and fixtures) 41 42

❌  Loose tiles.
❌  Drumminess (misses in bedding) over more than 10% of each individual tile.
❌  Joints are misaligned or uneven.
❌  Tile joints have voids, cracks, pinholes or low spots when viewed from the normal viewing position.
❌ Grout is grainy or flaky, or dislodged from the joint.
❌  Joints are cracked or unfilled.

Lippage is no more than:
2 mm for a rustic or uneven tile surface with joints 2–3 mm wide
1.5 mm for a standard tile surface (e.g. smooth porcelain tiles) with joints 2–3 mm wide
1.0 mm on flat abutting tiles (e.g. marble or granite).

✔️ Joints are consistent in width and depth and installed to specifications.
✔️Tiled surfaces are flat to within ±4 mm for every 2 m of length (unless otherwise specified)
✔️ Tile layouts have been set out from the center line of the space or surface being tiled, or as specified.

❌  Tiles or grout are stained at handover (staining after handover is not considered
the main contractor’s responsibility unless due to a deficiency in the specified sealing coat).
❌ Sealant or grout has been left on the tiled surface.
❌ Tiles have not been blended according to the manufacturer’s recommendations.*41
✔️Grout is a consistent colour and texture when viewed from the normal viewing position and does
not contain dirt, debris or residue on hand over.
✔️ Uniform colour variation of grout within 12 months.
✔️Sealant has been used to fill joints at wall/floor and wall/wall intersections to accommodate movement.*42

*41 Tiles of the same type may vary in colour, texture and pattern and this should be expected.
*42 Slight variations between the colour and gloss of sealant and grout are to be expected due to being two different products.
Unless otherwise specified, installation of sealant that is an entirely different colour to the grout is a defect.

❌  Damage during work done as part of the contract.
❌ Tiles have surface chips, scratches and abrasions at handover that are visible at the normal viewing
position of ≥ 2 m.
❌ Tiles do not retain the manufacturer’s intended shade, texture and appearance despite correct
specification for the intended application and correct cleaning procedures.