Small repair, awkward position
A single tile near a low eaves may be quick to reach. The same tile above a conservatory, narrow alley or three-storey drop is a different job because safe access takes longer and may need specialist equipment.
Scaffolding changes the arithmetic
People are often surprised by how much of a quote is access rather than roofing material. That is normal on some jobs. Ask whether scaffold, tower or other access is included so quotes can be compared properly.
Hidden timber damage
A leak that has been running for months can soften battens, decking or fascia timber. Nobody can price hidden decay perfectly from the pavement. A sensible quote should explain what is known and what would count as extra work if uncovered.
Materials and matching
Common concrete tiles are usually easier to source than an unusual old slate or discontinued profile. Leadwork is priced differently again because the labour and material are both significant.
Get the scope in writing
“Fix leak” is too vague for comparison. A useful quote should say which area is being repaired, what is being renewed and whether making good is included. That is more valuable than chasing a single headline number.