In which cases am I required as a professional to provide the odometer reading and description of the work carried out?

At each maintenance and service, at each mechanical, electrical, electronic repair, or body repair and at each replacement and assembly of parts, components or accessories. 

This means the odometer reading and the description of the work also have to be filled in whenever work is carried out on tyres, exhausts, batteries, radios, alarm systems, etc.

Do not fall under the law: vehicle wash and vehicle recovery without repairs.