Separate the evidence
A presentation box, dated warranty card, sales receipt, service invoice, spare links and reference-specific accessories do different jobs. List every item separately so a buyer can see what supports provenance, fit, future cost and resale confidence.
Let the reference decide the premium
Completeness can matter more for collectible, discontinued or configuration-sensitive watches than for common modern examples. There is no universal percentage because buyers pay for the confidence and scarcity that the exact reference makes useful.
Put service paperwork in context
A detailed service record can reduce uncertainty about work already completed, but it must name the provider, date, scope and replaced parts. Service can improve function while changing originality, so the paperwork should be read instead of merely displayed.
Do not let accessories hide condition
A complete set does not repair soft case geometry, damaged parts, weak timing or an unclear ownership story. The watch itself remains the primary object; the supporting file earns its place only when it helps a buyer understand it.
Use transparency to protect the range
State what is included, what is missing and what cannot be confirmed. A clear evidence file lets buyers place an example inside a credible range and reduces the late-stage renegotiation that follows vague descriptions.