Herod wrote;
I've got mine, but it's printed on shiny paper!. No use at all in the smallest room.
I realise that this was written to attempt comic effect, but on a serious note I found it very useful to have kept my newsletters some time ago.
HMRC wanted me to pay around £4,000 and I appealed against it using Extra Statutory Concession A19. It was the copies of the newsletters that convinced them that the errors had not been mine, but the pension provider. I'd hang on to at least the latest one, if not all of them.