The Block Hours discipline.
Capped retainers protect against scope creep. But ad-hoc work happens, campaign launches, brand-launch collateral, post-acquisition website integration, season-led creative cadence. How we handle it without surprise invoices: the Block Hours pool.
The mechanic
Ad-hoc work is commissioned from a known Block Hours pool. Bulk-purchase discounts available (e.g. 20-hour pool with 4.17% discount, 40-hour pool with deeper discount). The hours are commissioned by the client, not consumed by the agency. Every hour's use is documented and reconcilable.
Why this works better than "extras"
Three things go wrong with the unspecified-extras model that the Block Hours model fixes:
1. Trust survives
When a client opens a Xero invoice and sees a line they didn't authorise, trust dies. When a client opens a Xero invoice and sees "16 × Block Hours " against work they specifically commissioned, trust survives. Same dollar amount, completely different relationship trajectory.
2. The cap stays the cap
Charleston's cap holds because Block Hours are explicit and additive, the cap is a firm. The cap doesn't quietly creep upward; it stays, and additional commissioned work appears on a separate, transparent line.
3. Internal discipline
Block Hours force the agency-side to be honest about what work is in-scope vs out-of-scope. When the senior strategist sees a request that's borderline, they have to make a call: absorb it within the cap, or flag it as Block Hours work. Either decision is fine; the silent third option (do the work, don't flag it, then bill it as a "miscellaneous" extra) is the one Block Hours rule out.
What we use Block Hours for
- Campaign-launch collateral surge (one-month spike in creative production)
- Award submission strategic copy (Berg Engineering pattern)
- Post-acquisition website integration (PYBAR / Thiess pattern)
- Season-led creative cadence (FIS for fertility, Mother's Day for consumer brands)
- Ad-hoc Shopify or WooCommerce customisation (Bujairami pattern)
- Recruitment landing page builds ( each, charged separately)
- v1.1 / v1.2 site iterations after launch (Marrambi Estate FHB pattern)
For brands evaluating us
Two questions worth asking any agency you're evaluating:
- If we ask for ad-hoc work outside the retainer scope, how do you handle it commercially?
- Can you show me a sample invoice with both retainer and Block Hours lines on it?
"It's covered in the retainer", beware. That answer is how scope-creep eats agency margin and how surprise invoices appear three months later. "We use a Block Hours pool, here's a sample invoice", that's the answer that suggests an agency with operational discipline.
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