The best classification scheme is the one your organisation actually applies consistently. Over-engineering is the most common reason schemes collapse.
Keep the top level short
Three or four sensitivity levels — for example Public, Internal, Confidential, Restricted — cover the vast majority of needs. Every extra level multiplies user decisions and training cost.
Map levels to handling rules
Each label should imply concrete handling: who can access it, whether it can leave, whether it must be encrypted. If a label changes nothing downstream, it is decoration.
Make the right choice the easy choice
Suggested labels, sensible defaults and policy-based automation mean most files are labelled correctly without a human deciding each time. Veriket combines manual, automatic and AI labelling so coverage does not depend on discipline alone.
Review and evolve
Revisit the scheme as data and regulation change, and use discovery to check that reality matches the policy.