Skip to content
allanninal.dev/build
Collaborate

Part 4 of 7 · Holiday accrual tracker series ~5 min read

Booking time off, and the three reasons a balance survives the year

A balance moves for two reasons: leave is taken, or a year ends. The first is simpler than most systems make it and the second is more complicated than most spreadsheets admit, and both failures point the same way.

Key takeaways

  • A request reserves. Only leave actually taken deducts.
  • Deduct from the pot that expires first, which is the answer that favours the worker.
  • Sickness carry-over is capped and expires 18 months after the year it accrued in.
  • Family leave carries the whole entitlement into the following year.
  • Where the employer never gave a real chance to take it, the balance keeps accumulating.

A request is not a deduction

A leave request moving from reservation to deductionA vertical chain inside an AWS account container, entered from a box on the left labelled A leave request with dates, hours and a worker. Check the balance projects it forward to the requested dates, with a side exit reading insufficient: Tell them, with the number rather than just a no. Reserve it makes the request visible but not yet deducted, with a side exit reading cancelled: Release, the reservation removed and the balance restored. The dates pass, meaning the leave was actually taken. Deduct takes it from the pot that expires first. Write the line appends a negative entry recording the pot it came from. A note says deducting at request time makes the balance go backwards when somebody cancels, and a balance that goes backwards is a balance nobody trusts.AWS ACCOUNTA leave requestdates, hours,and a workerCheck the balanceprojected to therequested datesTell themwith the number,not just a noinsufficientReserve itvisible, but notyet deductedReleasereservation removed,balance restoredcancelledThe dates passthe leave wasactually takenDeductfrom the pot thatexpires firstWrite the linenegative, with thepot it came fromDeducting at request time makes the balance go backwards when somebody cancels, and a balance that goes backwards is a balance nobody trusts.
Fig 1. Five steps and two ways out. The distinction between reserved and deducted is the whole reason the projected balance can be trusted.
  • Database
  • Security & identity
  • Management
  • Analytics

Projected, not current

The number a worker needs when they are booking August in February is not their balance today. It is what their balance will be in August, given the accrual they are expected to earn between now and then and the leave they have already reserved. Those are different numbers and the second is the useful one.

The projection is deliberately conservative: it accrues forward at the average of the last complete quarter rather than the best one, and it treats every existing reservation as if it will be taken. A worker told they can book and then told later that they cannot has been failed by the system, and the failure is expensive in a way that does not appear on any ledger.

Three reasons a balance crosses the year end

Three carry-over routes converging on one carried balanceThree boxes on the left feed one box on the right. Sickness, where the worker could not take leave because they were ill, is capped and lasts eighteen months. Family leave covering maternity, adoption and shared parental leave carries the whole entitlement. Employer failure, where the worker was never told about the entitlement or never given the chance to take it, accumulates. All three converge on Carried balance holding an amount, a reason and an expiry, which feeds a box labelled Next leave year, opening with the carried hours in it. A note says three routes mean three different amounts and three different expiries, that a single carry-over field cannot tell them apart, and that they are settled very differently.Sicknesscould not take itbecause they were illcapped, 18 monthsFamily leavematernity, adoption,shared parentalthe whole entitlementEmployer failurenever told, nevergiven the chanceaccumulatesCarried balanceamount, reason,and expiryNext leave yearopens holding thecarried hoursThree routes, three different amounts, three different expiries. A single carry_over field cannot tell them apart, and they are settled very differently.
Fig 2. Three quite separate rules that happen to have the same effect on a balance. Which one applied is recorded, because it determines when the hours die.
  • Security & identity
  • Management
  • Analytics
  • People

The third route is the one that surprises people

The first two are foreseeable: somebody was off sick, or somebody was on maternity leave, and in both cases the business knows it happened. The third is different, because it is a finding about the employer’s own conduct, and no employer files that finding against themselves in advance.

The substance of it is straightforward. If a worker was never told what they were entitled to, or was never realistically able to take it, or was never warned that it would be lost at the year end, then it is not lost at the year end. It keeps rolling forward. For a business with a pool of bank staff who have never been sent a balance in their lives, that is not a hypothetical.

Which is, in a sense, the strongest argument for building this at all. A system that sends every worker their balance and a note saying what happens to it at the year end does not only produce a tidier ledger. It converts an open-ended accumulating liability into an ordinary one that expires on schedule.

What a carry-over line records

  • Amount. In hours, from the closing balance of the year it accrued in.
  • Reason. Sickness, family leave, employer failure, agreement, or a moved leave year.
  • Source year. Which window it was earned in. Not the one it lands in.
  • Pot. Which of the layers it came from, because they expire differently.
  • Expires on. A date, computed at the time, never recomputed later.
  • Evidence. What supports it — the sickness record, the leave dates, the notice that was or was not sent.

Which pot leave comes out of

When a worker takes a week off, the system has to decide whether that week came out of carried hours from last year, this year’s four-week pot, this year’s 1.6 weeks, or contractual extra. Nothing tells it, so it needs a rule, and the rule is to spend the hours that expire soonest.

That is the answer that leaves the worker with the most usable entitlement at the end of the year, which makes it both the fair default and the defensible one. It is also the answer that minimises the carried balance, which is what the finance side wants, so this is a rare case where nobody has to lose an argument.

The next post is the last day: what is owed when somebody leaves mid-year, why it is the number former employees check most carefully, and what the record has to contain for the answer to hold up.

All posts