What supervision is actually for
Supervision exists to catch the gap between what was agreed and what happened, before you have to. Its value is not in the visit itself but in what follows: a task corrected, a method adjusted, a periodic item scheduled. If a provider cannot describe an outcome from a supervisory visit, the visit is a presence rather than a control, and you will still be the person noticing problems first, which defeats the purpose of paying for oversight.
It also protects continuity. A cleaner who works unsupervised for a year will develop their own version of the scope, usually shaped by time pressure rather than by the document. That drift is gradual and reasonable from their side. Supervision is the mechanism that keeps the arrangement anchored to what you actually bought, which is why it matters more the longer a contract runs and the longer the drift runs the harder it is to correct.
