Three models, three risks
| Model | The client buys | Your risk |
|---|---|---|
| Availability | Priority access and a guaranteed response time | Low. You are paid for reserving capacity, whether or not it is used. |
| Block of hours | A set number of hours each month | Medium. Unused hours become a debt in the client's mind unless the agreement says otherwise. |
| Outcome | A defined deliverable each month | High. Effort varies, the fee does not, and a bad month is yours to absorb. |
Most disputes come from a retainer sold as availability and used as a block of hours. The client counts what they got; you priced what you reserved. Both are acting in good faith and the agreement never said which one it was.
The rollover clause
The single most important sentence in a retainer, and the one most often omitted:
Unused hours do not roll over to the following month unless agreed in writing.
Without it, a quiet January becomes ten hours the client believes they own in February, on top of February's ten. Do this for a year and a client can arrive in December expecting forty hours of free work — and from their side, entirely reasonably.
The clause is not harsh. What the client bought was your availability in January, and you provided it. If you want to be generous, allow rollover for one month only and say so — a stated limit is generosity, an unstated one is a liability that compounds.
Pricing availability
If the retainer covers up to ten hours a month, the fee is not ten times your hourly rate. That would price it as a block of hours you happen to be certain about, which is backwards: reserved capacity is worth more than sold hours, because you turned down other work to hold it.
The common shape is a premium on the reserved portion and a lower rate on work beyond it — the opposite of a bulk discount. A worked example at €85/hour:
| Element | Basis | Amount |
|---|---|---|
| Retainer, up to 10h/month | 10h at €95 (reserved premium) | €950 |
| Hours 11–20 | Standard rate | €85/h |
| Beyond 20h | Requires written approval first | €85/h |
The third row matters as much as the price. An approval threshold turns a surprise invoice into a decision the client made.
Term and exit
Monthly renewal with 30 days' notice on both sides is the usual balance: long enough that you can plan, short enough that the client does not feel trapped into signing. Annual commitments look attractive and are harder to sell — and a client who has to be locked in was going to leave anyway.
Say what happens to work in progress at the end, and say that the last month is invoiced as normal. A retainer that ends mid-project with no clause about it ends in an argument about the final invoice.
Get it signed instead of reading about it
The demo is the real product with example data in it. No account, nothing to install, and anything you add you can keep when you sign up.
No account to look around. Example data, and anything you add is yours to keep.
Questions
Should the retainer be invoiced in advance or in arrears?
In advance, at the start of the period. The client is buying availability for the month ahead, so billing after the fact reverses the logic and hands you the risk of a month you already reserved.
What if the client uses far fewer hours than the retainer covers?
That is the arrangement working as intended — they bought priority access and you held it. If it happens for several months running, raise it yourself and propose a smaller retainer. Clients remember being told they are overpaying.
Can I raise a retainer fee?
Yes, with notice — 60 days is polite, and lands better alongside a short note on what changed. A retainer held at the same price for three years is a price cut you gave yourself without noticing.
Does Flowzivo handle recurring retainer invoices?
Yes. Mark the invoice recurring and the dashboard raises the next one when it is due, with a fresh number in sequence and the period generated from the date. Nothing is sent without you confirming it.