Although I am computer literate and use a computer all day long, I am very phone illiterate.
I am in a "pocket" and mobile does not work well, so I rarely use it.
I do not know how to put things in a diary on my phone, so I use an actual diary.
I write all my appointments and social engagements on a calendar at home. I'm not very good at using the diary on my phone, but I suppose I would get into the habit of doing it after a while. I am pretty good at remembering my diary dates, despite being terribly busy.
same for me. You have to have time to get into a phone or laptop computer (which means remembering another thing to do). Before me eyes, in the kitchen, no problems. And, because it's on view to everyone, family members remind one another of what's needing to be done, so it's a back-up system.
I have never carried or used a diary in my life so it was easy for me to start putting things in my phone. I also write things on the wall calendar that only pertain to home: dog worming, flea treatments etc.
I have ALWAYS used a small diary in my handbag. I started writing a diary in '62!!! Then I used to get a free 1 from the Blood bank in the Dec when I donated (my blood) Now they don't have them anymore, because not enough people were taking them. Now I have to buy them from a bargain shop. I buy the lightweight 1 I can find. I also have 1 on my laptop I use every day, & our investment firm posts us 1 every year with beautiful Australian photos in them of birds & wildlife. I still have them all. That's always kept on the small table with the landline phone on it, to jot down appointments. I love my diaries, & I still have them all. I started a diary at boarding school just in case the police ever asked me where I was on such 'n such a date. Yes, crazy I know! (And no, they've never asked me. No, I've never worked out how to put them into my phone!
I do both but use a wall calender so I can see at a glance what is coming up ( i transfer every year to new calendar and no I don't find it boring) and use the phone with alerts, The phone diary is a double up but that doesn't bother me....