+1I'm afraid that I tend to be a bit of a magpie where deceased relatives affairs are concerned in my capacity as an executor.
Apart from tax affairs, if things happened of which you were previously unaware you could have people coming at you some years after death. (I am not talking about time limits for commencing proceeding against an estate after death.)
I certainly found retention of old documents very handy when a little problem surfaced and I was able to sort it rapidly as I had the paperwork to exhibit.
Therefore, I would keep copies or originals of relevant paperwork in archive type boxes and keep them in the attic. Sod's Law says that as soon as you dispose of something you will need it next month when a problem surfaces .
It would be prudent to retain forever records, whether with public or private sector bodies, that relate to 'life events', e.g. http://www.citizensinformation.ie/en/lifeevents/. Some examples from the Revenue Commissioners https://www.revenue.ie/en/life-events-and-personal-circumstances/index.aspx and a good list from the Pensions Authority https://www.pensionsauthority.ie/en/LifeCycle/Important_life_events/. Documentation relating to certain events, e.g. asset acquisition, property purchase, planning permission, etc. may be required by executors, descendants, etc.+1 I advise my customers to retain records indefinitely, for this precise reason. I've seen cases where the destruction of even old photos with zero sentimental value has later haunted people when these and other items were needed later as evidence when a totally unexpected dispute later arose.
I know it is a bloody nuisance but I keep everything going back 30 years to my father in laws death and will. Since then I have at least on three occasions had need to source documents to solve disputes. The solution was always to the benefit of the family member I was assisting. I have no doubt the legal profession would have made a pretty penny out of the cases if I hadnt the documents.Thanks everyone. Typical - I don't have an attic.