When you renew every three years, you’ll sign a declaration saying you’re fit to drive. This is a self-assessment, not a pop quiz. No one’s going to follow you to the shops to grade your parking.
But be honest, please. If your nighttime vision has gone a bit “impressionist painting,” maybe avoid driving after dusk until you get it checked. No one wins by pretending foggy headlights are LED halos.
UK Driving Licence Renewal Rules for Over-70s – Surf Radio Falmouth
Think about your own comfort, too. If you feel tired on long trips, take breaks. Stop for a cuppa—British highways run on tea and digestive biscuits.