Utilisation is the number that runs a professional services career, and most graduates take a year to work out what it actually measures. It is the proportion of your available hours that get charged to a client, and a target of 75 to 85 per cent is standard across consulting, accounting, and law. Anything that is not billable is, in the firm's accounting, a cost.

The trap is that plenty of genuinely valuable work sits outside the definition. Proposal writing, internal training, and mentoring a first-year all fall into the non-chargeable bucket, which means an enthusiastic junior can spend six months being useful to everyone and finish the year at 68 per cent. That number will follow them into a review conversation where nobody mentions the proposals.

Timesheets compound this because they are usually filled in on a Friday afternoon from memory. Studies of time recording consistently find people misallocate 15 to 20 per cent of their hours when reconstructing a week retrospectively, and the errors are not random — they systematically favour whatever the person did most recently. A daily habit of recording as you go is worth more to a career than any amount of after-the-fact reconstruction.

There is also a strategic dimension that rarely gets explained. Being staffed on a fixed-fee engagement that has blown its budget is materially worse for your numbers than being on a time-and-materials job of equal length, because the write-offs land somewhere and it is rarely the partner. Asking about fee structure before agreeing to a secondment is a reasonable question, not an impertinent one.

The point is not to game the metric. It is to understand that a career gets assessed through a system that captures some of your contribution and misses the rest, and that behaving as though it captures everything is a slow way to be undervalued.