A scuff up to roughly 50mm of total circumference on the rim face is commonly treated as acceptable wear, but any damage to the spokes, fascia or hub is judged far more strictly, sometimes regardless of length. Check each wheel with the car clean, not dusty: brake dust hides scuffs that jump out the moment the wheel is washed.
Tyres have a legal minimum of 1.6mm, but most lease companies apply a stricter internal figure closer to 2mm. Check the sidewalls too, not just the tread: a bulge, cut or repair patch there is treated as a safety issue regardless of tread depth. Some lease companies also specify the exact brand and model of tyre that has to go back on, not just an equivalent size and rating, so check your own agreement before replacing anything.
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