Notice Period Maths: Planning the Twelve Weeks After a Resignation

Someone resigns on a Monday. The team relaxes slightly because there is a notice period, and a notice period feels like time. Then the leaver's last day arrives, the replacement has not been hired yet, and the work has to go somewhere.

The maths that matters is this: the knowledge leaves on the last day of notice, but the replacement becomes useful only after they are hired, serve their own notice, and ramp up. Those two dates are almost never close together. Draw both on one line before you do anything else, and plan for the gap between them rather than hoping it is small.

Draw the line first

Take a sheet of paper and mark five points along it. Use your own organisation's real durations, not averages from an article, because notice periods and hiring speed vary enormously by country, role and contract.

• Resignation day. Today.
• Last working day. Resignation day plus the notice period in their contract.
• Offer accepted. Whenever your hiring loop realistically finishes, counted from the day the role is actually approved and posted, not from the day of resignation.
• Replacement starts. Offer accepted plus their notice period at their current employer. If they are relocating to Dubai, the practical first month questions belong in that span too.
• Replacement is independently useful. Start date plus ramp up, which is also the window a probation review should be collecting evidence across.

Two of these are outside your control entirely. The gap between "last working day" and "replacement is independently useful" is the hole you are planning for. In most teams it is considerably longer than the notice period itself.

The part people get wrong

The mistake is treating the notice period as hiring time. It is not. Hiring only starts when the role is approved, and approval frequently takes days or weeks after the resignation, especially if a budget holder wants to think about whether to backfill at all.

Every day spent deciding whether to replace someone comes straight out of the overlap. If you are going to backfill, approve it in the first week. If you are not, say so in the first week, because that changes the handover completely.

Spend the notice period on the right thing

The instinct is to have the leaver finish their in flight work. That is usually the wrong call.

The best use of a notice period is transferring what only they know to people who are staying. Finishing a feature helps for a month. Writing down how the payment retry logic actually behaves helps for years.

A workable split:

• First third: list everything only they know, honestly and without diplomacy. Systems, relationships, undocumented decisions, the client who always calls on Fridays.
• Middle third: work through that list with a named receiving person for each item, doing the task together rather than describing it.
• Last third: the receiving person does the task while the leaver watches. Then finish or hand off whatever in flight work remains.

If you only do one of these, do the middle one. Documents written alone in the last week get read by nobody.

Name the receiver, not the team

"The team will pick it up" means nobody picked it up. Every item on the knowledge list gets one name next to it, and that person's own commitments should be adjusted to make room. If you cannot adjust their commitments, the handover will not happen and the list is decoration.

This is also the moment to notice that you now have a single point of failure again, just a different person. Where the item is genuinely critical, put two names on it.

Plan the gap, not the wish

Once the line is drawn, you know the length of the hole. Now make three decisions before the last working day:

• Which commitments in that window move, and who has been told
• What work stops entirely for the duration, chosen deliberately rather than by accident
• What contract or temporary help, if any, is worth it, and for which specific piece

The third one is often dismissed on cost, but compare it against the delivery days lost rather than against the salary saved.

Keep the two calendars together

The reason this planning happens late is that the resignation lives in HR and the commitments live in the project tool. The people who know the last working day and the people who know what is promised in that window are usually looking at different screens.

Systems that keep both on one set of records remove the lookup. SicherOne is built that way, with project management and HR on the same records, so a notice period is visible on the plan it affects rather than in a separate file. Sold per seat, with modules separable.

The habit matters more than the software. On the day someone resigns, draw the line. It takes fifteen minutes and it is the only part of this that gets easier the earlier you do it.