State what the recurring fee actually covers
- The basis — per device, per user, per site, or a flat contract
- The count it was billed at this period, and the unit price
- What is included: monitoring, patching, backup, helpdesk hours
- The response times that come with it, if your agreement sets them
A recurring line showing "42 endpoints at the contract rate" survives a headcount change; one showing only a monthly total does not, and every hire or departure becomes an email.
Bill overage against a stated allowance
Where the retainer includes a number of hours, show the allowance, the hours used and the hours billed beyond it. Overage that appears without the allowance beside it reads as a surcharge rather than as the term it is.
Licences and hardware are pass-through, and should look like it
Subscriptions you resell, hardware you procure and third-party services you administer belong in their own section, with quantities and the period they cover. Blending them into a service fee makes the client's own cost allocation impossible and hides your actual margin from you as well.
Out-of-hours and emergency rates need to exist before the emergency
An after-hours multiplier agreed at contract time is an ordinary line on an invoice. The same figure invented after a Saturday outage is a bill somebody escalates on Monday.
Common questions
- Should I bill monthly in advance or in arrears?
- Recurring support is usually billed in advance — it is availability rather than delivered work — with overage and project time billed in arrears on the same invoice or a separate one.
- How do I handle a client whose device count keeps changing?
- Bill the count on a stated day each month and say which day on the invoice. A moving count with no reference date is a dispute every quarter.
- Should ticket detail be on the invoice?
- A summary count, yes; the tickets themselves, no. A client who wants the detail can be sent the report, and an invoice carrying forty ticket lines invites a review of all forty.