Independence is what makes a check meaningful
A cleaner reviewing their own work at the end of a shift is a useful discipline and not an assurance process, because the person assessing is the person who did the work. Assurance requires somebody else looking, whether that is a supervisor, an area manager or a periodic audit by another part of the business. Ask who performs the check and what their relationship is to the cleaner.
Ask how often it happens and whether the frequency is higher during mobilisation. Most arrangements need closer attention in the first months while the site is learned, and a provider proposing an identical frequency in month one and month twenty has chosen a number for the proposal rather than for the work. That pattern is easy to spot and worth asking about and it usually indicates how much thought went into the rest of the proposal.
