I should keep all your annual P60's (the form you get from your employer once a year telling you how much tax & N.I. you've paid). The reason is that Government records are not as efficient as they would like you to believe and many people have had disputes about how many years' NI contributions they've made which determines what your State Pension will be. Get yourself a folder to store them in and keep them until you retire just in case of dispute. In any case, your payslip and P60 is a useful document for proving your identity if you want to open a new bank or building society account (because of tightened money laundering regulations).