Hi there,

First of all, may i know which year model of your Vios?
As for Lifetime guarantee, We guarantee our wiper blade itself will not harden, crack, rotten, melt or sticky for as long as you own your vehicle. We will replace 1 on 1 if those mentioned problems occur at no extra cost.
Means you only purchase 1 set wipers from us and use for as long as you own your vehicle.

Thanks for your interested.