As Mr Mixer says all aircraft need some form of pre-flight inspection - be it a microlight or an A380. So, applying that knowledge, there is not a weight or Pax limit / restriction.
The term varies from type-to-type between:
Pre-Flight Inspection,
Pre-Departure Inspection,
Before Flight Inspection,
Before First Flight Inspection,
Daily Inspection, or even
'A' Check (or even Check 'A')
Depending on the Maint Schedule for that aircraft that particular inspection / check would normally qualify for needing a CRS and as such would need the certifier to hold an appropriate licence or be an approved pilot.