Aaaargh, yet again we face an overdue and extra-expensive fine for something (driving down one of those roads with a completely missable no-cars sign in this case) because DH almost never opens his post. It's like 3 times a year, tops. I'm quite sure he thinks he goes through his post every couple of weeks, but no, it's about every 4 months. Honestly, once he decided to take his post on the train to the airport for a holiday, and he found, among other things, an HMRC demand for £500 (paid, fortunately) and a cheque from them for nearly £10k that we then had to carry around on our holiday!
I am not going to open his post, because I am not making it my responsibility, it is his.
I immediately open anything that doesn't look like junk mail or something I know is regular - not much anymore because I do most things paperless now, but I never leave things for months on end.