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'm pretty sure some of my T-shirts could win this if we don't take this whole "daily" I aspect too seriously. There are a few from my teenage years that are still in good shape and still fit, which I've had for literally more than half my life by now.
That "daily"-aspect makes it really hard though, since there are days when I don't even need my house keys. Lighbulbs die after some time, so they ain't it either. And would wardrobes count as "items"? I tried thinking about this question so hard for way longer than I probably should've now, and got to no unanimous conclusion so far. But in the end, it doesn't even matter, so I'll just go with: probably my glasses
I struggled with the same thing. I’ve got some ties from my dad from haberdasheries that hadn’t existed for a couple of decades before I was born. They are in regular rotation but that means they get worn once every few months like all my other ties.