IFRS 15 requires revenue to be recognized over time if any of the following criteria are met:

1. The customer simultaneously receives and consumes the benefits provided by the entity’s performance as the entity performs: This is typically the case with many service contracts. For example, a cleaning company providing ongoing janitorial services would recognize revenue over time as the services are rendered, since the customer is consuming the benefits simultaneously.
2. The entity’s performance creates or enhances an asset (for example, work in progress) that the customer controls as the asset is created or enhanced: This often applies in construction or manufacturing contracts for bespoke items. A construction company building a custom-designed property on a client's land would recognize revenue over time, as the client controls the asset (the building) as it's being created.
3. The entity’s performance does not create an asset with an alternative use to the entity and the entity has an enforceable right to payment for performance completed to date: This may apply in some long-term manufacturing contracts. For instance, if a shipbuilder is constructing a highly customized ship for a customer and cannot repurpose the work-in-progress for another customer, and it has a contractual right to payment for work completed, it would recognize revenue over time.

Please note that if none of these criteria is met, the performance obligation is satisfied at a point in time, and thus revenue is recognized at that point in time.