it all depends on the model you have.
the prefacelift unfortunately have the arm and blade as one unit so you'd need to replace thee entire arm should your blades be shot.
the facelift models are different, the blades are interchangeable allowing one to just replace the blade/s when they're shot.
changing the blades/arm is very easy and you don't need to take it a garage if you can source the stock yourself.
the prefacelift as I stated need to have thee entire arm removed and all that's needed to do is a 10mm socket, remove the nut and pull the arm forward.replacing the arm I would recommend you try and source the facelift model arms and then buy new blades.
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