1. Define what the contract covers
Visits per year, the units covered by model and serial, labour on visits, and whether spare parts are free or charged. Most disputes come from that last point.
2. Price on real cost
Visits × (technician time + travel), plus a buffer for breakdowns between visits if covered. If parts are free, add the average parts cost per unit per year.
3. Visits schedule themselves
A contract with a visit every three months must create the visit job on time for the assigned technician without anyone remembering. Late visits are the first reason customers do not renew.
4. Record every unit and its history
Each unit with model, serial, install date and warranty, plus every service done on it, so the technician knows what was fixed before.
5. Technicians close jobs from the phone
Diagnosis, resolution and parts are recorded at the customer. Parts are deducted from stock and, if not covered, added to the invoice.
6. Renew before expiry
A month before the contract ends, send the customer a summary of the year: visits done and issues fixed. That is the strongest reason to renew.