Fixing screws tight, but furniture loose on door
Furniture screws too long.

Furniture screws difficult to tighten
Burrs on screws – Must de-burr screws when cutting to length.

The holes previously drilled in the door are too small for door furniture I purchased
In a retrofit situation, if the previous door furniture is old often the holes drilled for the furniture are not suited to the new furniture and may need modification.

The backset for the door furniture is not the same as previous door furniture
In a retrofit situation, if the previous door furniture is old it may have a different backset - Many of the new door furniture products have adjustable backsets built into the latches.

How does the emergency release function on the privacy sets work?
There will be a release, turn button or other device built into the door furniture to allow access in the event of an emergency.