Scout said:
At least a year.
With a battery replacement, it could last 5+ years.
My first iPhone was the 2020 SE. I had it for a month before upgrading to the iPhone 16 Plus. I always kept it in an OtterBox with a screen protector, and I only upgraded because I was tired of charging it 2-3 times a day. I also have a 4S I got last year, and after changing the battery, it still works fine. As long as you take care of it, your phone should last as long as you need it to, except when updates and support are eventually discontinued.
What storage size did you get?
I had the iPhone 6S, then the 13 Mini, and now I’m getting the iPhone 16 in ultramarine.
Maybe until tomorrow… if you’re lucky.