Ad Agency Contract Length: Should You Calculate 12 or 24 Months?

When you get a proposal for ad management, it often includes a minimum term. Three, six or twelve months are common. For your planning, though, another question matters more: Over what period do you calculate whether the ads pay off? That's why we compare the same scenarios over 12 and 24 months below.

Ad Agency Contracts: Contract Term and Calculation Period Are Two Different Things

• Contract term: How long are you locked in? How quickly can you get out?
• Calculation period: Over how many months do you spread one-time costs and look at revenue?

A short notice period is good for you. Even so, you should evaluate an investment in advertising over a realistic period. Ads need time until audiences, creatives and offer fit together.

What Changes with the Term

1. One-time costs get spread out. Setup and the Booster one-time payment occur once; revenue comes in every month.
2. Booster credit counts for longer. The credit runs for 24 months. Over 12 months, you count the full one-time payment but only half of the credit.
3. Monthly costs grow linearly. Retainer and budget fee apply every month, no matter how long you calculate.

Worked Examples: The Same Scenarios over 12 and 24 Months

How We Run the Comparison

Both sides invest exactly the same total spend. On the Plaith side, it consists of your own ad budget, the setup fee, the package price, the budget fee and, if selected, the Booster. On the classic side, we subtract the cost of management and videos from the same amount. The basis is the benchmark from the expert report (Start €1,885.96, Growth €3,485.39, Scale €9,083.40 per month). The rest goes into ads. We don't include an agency setup fee there. Agency surcharges on the ad budget (for example 5% on everything or 10% on the portion above €1,000 per month, expert report section 4.1) are deliberately not included, so Plaith's lead is, if anything, larger.

S2: Start Package, €5,000 Budget, €5,000 Booster, ROAS 4

Over 12 months, you keep €182,273 with Plaith, versus €154,654.92 with the classic model. Over 24 months, it's €371,045 vs. €289,812.84. Plaith's ROPS rises from 12.15 to 14.29, because the credit works longer and the one-time costs are spread out.

S8: Growth, €5,000 Budget, €5,000 Booster, ROAS 3

The pattern holds even with a conservative ROAS: with the longer term, Plaith improves from €2.20 to €2.28 in revenue per euro spent.

S3: Growth, €3,000 Budget, €10,000 Booster, ROAS 5

Here the Booster is large relative to your own budget. Over twelve months, only €12,000 of credit counts; over 24 months, €24,000.

One Peculiarity of the Comparison

In the classic model, ROPS can be higher over 12 months than over 24. That's due to the calculation method. At the same total spend, the full Booster one-time payment already flows to the classic side within the 12 months. There it becomes ad budget. So the effect is a result of the fair comparison, not an advantage of a short agency term.

What This Means for You

Choose the calculation period based on your plan, not the contract. If you want to build up your advertising over two years, calculate over 24 months. If you want to test first, calculate over 12 months and plan conservatively. In the next step, we take the Booster out so you can see the effect of the setup fee on its own.

Without a Booster: How Much Does the Setup Fee Matter?

Without a Booster, the setup fee is the only one-time payment. Example S1 (Start, €1,500 budget, ROAS 3) shows how it spreads out:

With Plaith, ROPS rises slightly from 4.19 to 4.45. In the classic model, "What you keep" stays negative in both periods, because fixed costs are high relative to the small budget.

What to Look for in the Contract Term

• Notice period: Cancelable monthly gives you the most freedom.
• What happens if you cancel: Is the setup fee kept? Do you get access to accounts, creatives and data?
• Minimum term and price lock: A long commitment in exchange for a discount only pays off if you're sure.
• One-time payments: How are they handled if you cancel early?

With Plaith: packages can be canceled monthly; the setup fee is non-refundable. With the Booster, if you cancel, you get the one-time payment back minus the credit already delivered, with a minimum of €0.

What the Booster Is

The Booster is an add-on module. Your ad budget then runs through Plaith instead of going directly to Meta. We pass our purchasing terms on to you as an ad budget package: for a one-time payment, you get one tenth of it as additional ad credit every month for 24 months, on top of your own budget. That turns €10,000 into €1,000 per month and €24,000 over the term. The credit is only valid with an active Plaith contract, is non-transferable, is not paid out in cash and is only used for ad delivery. If you cancel, you get the one-time payment back minus the credit already delivered, with a minimum of €0. If the platform's purchasing terms change, Plaith can end running packages with 30 days' notice; the same refund rule then applies. You'll clarify the exact terms in a call.

What You Gain When the Calculation and the Contract Are Separate

You want to build up your advertising for the long term, but without tying yourself to one provider for years. Short contracts feel safe; long calculations feel like they've been dressed up.

You plan over the period that fits your goal and still stay free.

What you get out of it:

• Freedom. Plaith packages can be canceled monthly. Only the setup fee is non-refundable.
• Realistic planning. You see how one-time costs spread out. In S2, Plaith's ROPS is 12.15 over 12 months and 14.29 over 24 months.
• Less pressure at the start. You don't have to decide up front how long you'll stay. You review continuously based on your weekly report.

Both periods are based on the same ROAS assumption. The conservative view remains 12 months.

Objections, Answered Honestly

There are three natural objections when it comes to contract length. Here's how we answer them:

"Calculating over 24 months is dressing up the numbers."

That's why we show both periods. 12 months is the conservative view, because one-time costs are spread over less revenue. Decide for yourself which period fits your planning.

"A long calculation means a long commitment."

Not with Plaith. Packages can be canceled monthly; only the setup fee is non-refundable. The calculation over 24 months is a planning framework, not a contract. The article Increase Your Ad Budget shows how the Booster plays out over the term.

"A short agency term is more flexible."

Flexibility is a real advantage. Still, calculate over your planning period. Otherwise you'll be comparing three months of agency with two years of Plaith and making the wrong choice.

Frequently Asked Questions

What contract length is common for ad agencies?

It varies a lot, and our expert report makes no statement about it. Check the minimum term, notice period and what happens to the setup fee in every proposal.

Over what period should I calculate?

At least 12 months, ideally 24. That spreads one-time costs fairly, and you see how Booster credit plays out.

Do I have to commit to Plaith for 24 months?

No. Packages can be canceled monthly. The 24 months in our examples are only the calculation period.

Further Reading

These articles go deeper on individual points:

• Increase Your Ad Budget Without Higher Monthly Costs: How the Booster Works
• Ad Cost Calculator for Business Owners: How to Run the Numbers on Meta Ads
• How to Compare Ad Agency Proposals: Checklist with a Worked Example

Run Your Own Scenario

Run your scenario over 12 and over 24 months. Then open the **Plaith calculator on plaith.ai**. Enter your package, your own ad budget per month and, if you like, a Booster. Then choose a conservative ROAS assumption, for example 3. You'll instantly see the ad budget, the cost paid to Plaith and the ROPS for your case. The same applies there: worked example, no guarantee.

Sources

• Expert report on the costs of Meta management and videos with real people, version of October 5, 2026: sample of documented offers, not a market study. Benchmark = average of the four Meta management packages (€1,086.25) plus videos at the average price of 224.42 US dollars, converted at 1.1225 USD per euro (sections 4.1 on p. 4, 5.4 on p. 11, 6.3 and 6.4 on pp. 14 to 17).
• Plaith's own calculations (as of October 6, 2026): package prices, budget fee, Booster and all scenario numbers in this article, recalculated exactly.