Do I walk away or dive in?
Go and have a look at it.
You can inspect the seats, steering wheel, pedals, switch faces for wear. You can look at the date code on the tyres. You can run your thumbnail on the brake disks looking for a wear ridge. You can look at the age of the battery and the dirt on the air filter. You can look for rust on the exhaust. You can look at the colour of the oil. You can look for dirt and road grit wear underneath. You can look for usage scratches round the keyhole. You can look at the bundle of MoT certificates and the originals of the service history.
There are plenty of older people who do very little mileage on their car but don't want to part with it. Garaging under cover will prevent paint fade, and moss growing in the window seals.