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Day 1 vs Day 100: What Belongs in Each Plan
The Day 1 plan covers legal structure, contracts, payments, system access, and communication to customers and employees, plus a clear answer to who decides if something breaks that day. The Day 100 plan is where the hardest decisions go, placed deliberately early, because deferring them is more expensive than making them unpopular but fast. Confusing the two, putting hard decisions into Day 1 or operational checklist items into Day 100, is a common and avoidable planning mistake.
What goes in each plan
| Day 1 | Day 100 |
|---|---|
| Legal structure and contracts finalised | Role overlaps resolved |
| Payments and system access working | Which systems win decided |
| Customer and employee communication sent | Office and site consolidation decided |
| A named decider for anything that breaks | Difficult, deliberation-heavy calls made early |
Why Day 1 is not the place for hard decisions
Day 1 has to work under maximum uncertainty and minimum information, it needs to be executable by people who haven't yet had time to properly assess the combined organisation. Loading it with judgement calls that need real analysis sets those decisions up to be made badly, under pressure, by whoever happens to be in the room.
Why Day 100 should front-load discomfort, not delay it
The instinct to preserve short-term harmony by deferring difficult calls, role overlaps, which systems win, which office closes, usually just extends the period of uncertainty. That uncertainty has its own real cost in attrition and stalled decision-making, which tends to exceed the cost of an unpopular decision made early.
A simple test for sorting an item into the right plan
Ask whether the item requires real analysis and stakeholder judgement, or whether it's purely operational and time-critical. Operational and time-critical belongs in Day 1. Anything requiring genuine deliberation belongs in Day 100, deliberately scheduled early within that window rather than left to drift.
The Deal Thesis Told You Where the Value Was. Did Anyone Translate That Into What Actually Has to Change?
We turn the deal thesis into a Day 1 plan, a Day 100 plan, and an integration office that protects the value you paid for, including the people who carry it.