I have not kept a paper diary for many years. My work and personal appointment diaries are all electronic, and are all synced to all my devices.
I run a work journal/to do list in Office 365 OneNote - it is superb for that purpose, and much else besides. I use it each day for meeting notes, diagrams, photos, and just about everything I need. It's all there, on my devices and in the Microsoft Cloud whenever and wherever I need it.
I do have a filing cabinet for inbound paper documents, but I hardly produce any paperwork at all - on average I print something about once every three weeks.
Everything is backed up on external drives, and in the Cloud. As long as the internet keeps going, I'm fine.