For average users, there is very little difference in the capabilities and features between the iPhone 12, 13, and 14…
- All are the same size.
- All have OLED screens (although, the average user wouldn’t notice even this vs the also very similar-featured non-OLED iPhone 11 unless they are next to each other).
- Their cameras, while slightly tweaked, are very similar.
A key difference configuration wise for the iPhone 12 - it starts at 64GB storage, a $50 at Apple MSRP gap vs the starting 128GB iPhone 13 and 14.
The iPhone 13 and 14 are truly nearly identical except the iPhone 14 has crash detection and emergency satellite communication if those functions are useful to you. However, if you like swapping out SIM cards when traveling, the iPhone 14 no longer uses physical SIM cards - it uses eSIM (virtual). The iPhone 13 can use either a physical SIM card or eSIM. This is the first time Apple did not jump a cpu generation between phone generations - both the 13 and 14 use an A15 cpu. (The iPhone 12 has an A14 cpu.)
Apple still sells all three phones, brand new, with 1 year Apple warranty.