What gets paid for two years later
An installation can be delivered working and be expensive ever after. The causes are always the same: unlabelled links, schematics that stayed with the installer, equipment stacked in the rack with no thought to access. The first fault reveals the hidden invoice, and it turns up again at every intervention. Labelling is a small line in the original quotation and almost always the first thing proposed for removal to meet the budget.
A rack is ordered by heat and access
The most common build order is the order the boxes were opened. The right order accounts for two things: what runs hot needs air above it, and what gets handled often belongs at hand height. A unit that is unplugged weekly, placed thirty centimetres off the floor behind two cable looms, will eventually be handled roughly, and the installation will carry the marks.