OT I know but wiper blades are one of the few 'car repair' things I do still deal with because MOT testers often fail a car for split blades and, to be fair, rotting rubber due to age (not mileage) is the cause.

I therefore replace the wipers every year just before the MOT is due - and I buy whole wipers from The Range for £1.99 each (total cost £5.97 for my hatchback).