Don't.
I believe I have upgraded to every phone since about the iPhone 5, but not this year. I fully expected I would. I have an 11 Pro Max. My reasons, much of which was feedback on these forums - these are the issues that seemed to be real and affect more than a small number of customers:
1) battery life appears to be worse than the 11's (people always complain about battery life at the beginning of a cycle, but last year there was much less and this year seems to be more - and 11 Pro Max users are saying it's worse);
2) 5G is a sham (tests scores are mostly the same as 4G or even worse, not many customers are reporting good speeds, even on Verizon);
3) 5G is a total battery hog (a popular question is "How do I turn 5G off?");
4) MagSafe doesn't charge even the 12 series very fast at all - 1/5th as fast? (and there have been reports of 1's having trouble charging on older wireless chargers too);
5) camera/pictures and video, and speed aren't really any better in real world use - I believe you would find low light pictures are better, the rest are the same;
6) no 5G speeds if you have 2 lines on your phone (Apple did say oops an update is coming to fix that).
That doesn't even get into all the little "one off" complaints that are likely non-issues but could turn out to be a true problem.
People on older phones - 6's, 7's, 8's - seem to love the 12's - that is a big jump for them.
Now time may prove some of these to not be an issue moving forward, software fixes etc. take care of some of these, maybe some engineering changes make some issues go away in phones manufactured in a month. But I really couldn't see a good reason to upgrade, and I became fearful that the experience would be worse than with my 11 Pro Max - whose performance is great.
My .02 for you!