I realised in my recent run of testing different used iPhone models that these days I’m favouring 128GB of storage. After using this amount now for well over a year, I feel that 128GB is the right size for most people.
If you’re plugged into the Apple ecosystem, odds are you’re using iCloud for your backup. For me I use it plus I pay for Apple Music. I also download a lot of my favourite music for when I’m on the go, which admittedly is less these days.
With that in mind my iPhone 13 with 128Gb is about half full. It’ll manage the moving files up and down from the cloud depending on how full this gets but I have no worries about my running out of space.
If you like to keep everything local, which I’m not sure why you would with cheap iCloud storage you’ll need to spend the extra on a larger 256GB or more iPhone.