A usability test is not about testing you as an experimentee but about testing a website or an app. The intention is to find out how well a product works for a user (just like you). Therefore you can‘t perform well or poorly, but you deliver useful feedback for further optimization of the product through your test.
Usually tests take between 15 minutes and one hour. Of course you’re informed about the test durations within any invitation.
You’ll receive an allowance for your participation. This depends primarily on the duration of the test, but amounts at least €15.
You can decide whether you’d like to participate a test or not anew for every invitation. Your registration is of course completely free of charge and without any obligation.