Two jobs that sound identical on the phone can be quite different once someone is looking at them, and understanding why makes a quote easier to assess.
Access is often the largest factor. A pipe in an accessible position under a house is a different job from the same pipe under a slab or behind finished tiling. The plumbing work may be similar; reaching it and making good afterwards is not.
Diagnosis versus repair is the second. Some problems are obvious on arrival. Others need investigation before anyone can say what the repair is, which is why a camera inspection on a recurring drain problem is not padding but the thing that prevents quoting blind.
Parts vary, particularly on mixers and appliances where components are model specific and some are harder to obtain than others.
Scope is the factor most often underestimated. Replacing a fixture like for like in the same position is straightforward. Moving it, changing type, or upgrading capacity may bring in additional pipework, drainage or compliance requirements.
A written quote that separates these elements lets you see what you are paying for and where a decision might change the total.
