Trial the real arrangement, not a sample of it
Providers sometimes offer a reduced trial and buyers sometimes ask for one, and both make the exercise less useful. A trimmed scope produces a result you cannot extrapolate, because the thing you are worried about is whether the full arrangement holds up under normal pressure. Run the actual schedule at the actual price, and accept that the point of a trial is to observe an ordinary month rather than a good one.
Make the length meaningful. Four weeks catches the routine but misses everything periodic, and periodic work is where most arrangements quietly fail. Eight to twelve weeks usually includes at least one scheduled periodic item, a public holiday and a staff absence, which are precisely the events that reveal how a provider operates when the schedule does not run perfectly and how quickly they recover the schedule afterwards without being chased.
