[petepete]

Not really. GOV.UK Design System team have done lots of research into this and their guidance says:

> Generally speaking, avoid validating the information in a field before the user has finished entering it. This sort of validation can cause problems - especially for users who type more slowly

https://design-system.service.gov.uk/patterns/validation/

[emodendroket]

Not seeing how that’s inconsistent with evaluating when the user goes to the next field.