Doesn't seem like a big enough improvement over the 12 to warrant the price difference? I'm on the iPhone X and will likely get the 12.
By far the biggest space user is music. I own thousands of CDs and so have a huge (and entirely legal!) iTunes library of over 50K songs. Back in the days of the 40GB iPod I kept it synced against a complicated smart playlist that tried to include what I was most interested in listening to... with very little success: any time something popped into my head I'd find it wasn't there.
The introduction of the 512GB iPhone models was the first time that I could sync it ALL to my mobile device, no compromises. Now does it make logical sense in the age of Spotify to have 4000 hours of audio synced to my phone? Probably not. However having access to even the most obscure material in my CD collection wherever I go (and even if I don't have internet access) gives me the sensation that I'm living in the future.
More broadly I tend to think of my phone like a biometric-protected SSD that I always have with me. I try to keep a lot of my personal files synced from my desktop to it (mostly using Secure Shellfish right now)
Currently, the 11, 12, and 13* are all listed for sale (on apple.com)
* Will be for sale this Friday
I have had an X since the day it shipped and the fact that its still a decent phone for daily use is a testament to how much of a leap it was at the time.
I was hoping to like the updates enough to justify the upgrade at this point, looks like I'll be waiting another year. If I upgrade any of the phones in my house it will be my partners, who will want a 12 because they can get one in purple. (Seriously Apple, why not may a 13 in purple, you'd get more money out of me that way)
I think it’s a pretty subjective call.