If its a defect in workmanship,pretty much forever.
Send it back to Burton McCall (the UK distributor and they usually will replace it,unless it was damaged through abuse.
You can replace the Blades if you have a little savvy.The pivot pins are retained by a sort of brass washer that is pushed over the pins on each side of the aluminium liners.You will need some 2.2mm brass rod as new pivot pins.make them about 1mm wider than the liners and then lightly pein them.Then replace those lovely red plastic scales with some nice wood.