The sequence is fragile. An electrician who does not arrive on Tuesday delays the plasterer, the units and the template, so a project plan that shows the knock-on effect is worth more than a list of jobs.
Some materials cannot be ordered early. A worktop is measured once the units are standing, which puts a fixed gap in the middle of every project, and pretending otherwise creates a promise that cannot be kept.
Stage payments protect both sides. Deposit, materials, first fix and completion agreed in writing prevents both the fitter financing a kitchen and the customer paying for work not yet done.
The last two per cent decides the review. A drawer that catches or a strip of sealant left undone is what a customer remembers and mentions, so a snagging list recorded and closed is the difference between a good job and a recommendation.