During the warranty period, the most important parts are made of paper. The receipt verifies your purchase date and ensures that you are covered for the full length of the warranty. You will also need to keep the instruction manual, as this contains valuable information specific to your unit. If paper seems kind of 90’s, consider retaining digital copies of the receipt and front cover of the manual, particularly any places where dates or alphanumeric codes are given. It may sound obvious, but it is also very important that you keep the unit itself until your ticket is resolved; please do not throw it away!