The terms overlap, but planning mainly depends on the actual scope.
'Clearance' may involve individual rooms or specific volumes. 'Household clearance' often describes clearing a household more comprehensively. In practice the exact work must still be defined.
For larger clearances there should be no ambiguity about personal documents, valuables, sentimental items or furniture that must remain.
Photos, a list of rooms and information on floors, lifts and parking are much more useful than the label alone.