Facility contracts are negotiated on frontline headcount. Supervisory strength is frequently treated as the contractor's internal matter, which is where many contracts quietly fail. Span of control in facility services depends on geography and complexity rather than on a universal ratio. A supervisor overseeing twenty housekeeping staff distributed across eight floors of one building can realistically verify work, address issues and support the team. The same supervisor overseeing twenty staff across three separate properties is performing travel, not supervision. Indicative ratios in practice fall between 1:12 and 1:20 for housekeeping within a single building, tighter where areas are complex or quality standards are demanding, and considerably tighter for specialist work. Security deployments typically operate at 1:10 to 1:15 per shift, with the critical requirement being supervisory presence on every shift rather than only on general shift. The night shift is where supervision is most often absent and most needed. A deployment with three shifts and one supervisor on general shift has unsupervised operation for sixteen hours daily. Supervisors require authority proportionate to responsibility. A supervisor who cannot approve a consumable requisition, adjust a roster or address a performance issue without escalating to an off-site manager will escalate everything or address nothing. For clients, the practical control is to specify supervisory strength and shift coverage explicitly in the contract rather than leaving it to the contractor's discretion, and to verify supervisory presence during site walks at unusual hours. Supervision is the mechanism by which a contract becomes a service. Its absence is visible everywhere except on the invoice.