Is the only answer a full refurbishment? The wheels on my 9-5 are original and reasonably tidy for their age, but two of them need topping up twice a week. Last week, during the cold snap, one of them went down completely overnight so I assumed a puncture. Took it to a tyre place who said no, it was leaking around the rim in multiple places and they would try to reseal it but recommended a refurb.
I refitted it and came out the following morning to a completely flat tyre. I won't be using them again! Threw some tyreweld in and it's held air better but still needed a top up.
What's to do? I don't particularly feel like chucking £50 a corner at a refurb when, as I say, they're cosmetically in fairly good order.