There is a HUGE difference in 4 and 12 GB of ram if you're using 20 different apps at once that are all running background tasks.

The camera raw megapixel are of little significance these days but things like optical zoom or a larger sensor and aperture make a lot of difference.

The main reason to upgrade otherwise is unsupported OS versions. you'll stop getting security updates leaving your phone vulnerable to attack.

It depends, your body does adapt overtime. the meds I'm on when I first took them knocked me out completely, now they do nothing in terms of alertness. I am now completely safe to drive on them.

reddit never let you do that, thankfully this does.