What item have you been using on a daily basis for the longest amount of time?
Sometimes I will use something and realize I've owned it forever. It's a nice change in our throwaway reality. I think my personal record is a bicycle multi-tool I got for one of my first bikes, ~25 years ago. Still have it, still use it. When it comes to electronic devices I have a Panasonic mini Hi-Fi from ~2005. Never felt like changing it.
I have my first generation Kindle Paperwhite that I still use daily, that is from 12. I don't think that is the oldest item I have in my possession that I still uses, but it is one that I have right be side me at the moment.
My Kindle keyboard is still going strong also. I bought it 13 years ago. I'm positive it's a dinosaur by today's e-reader standards, but it holds my books and renders pages just fine. I don't have a reason to upgrade.