So it turns out a lot of this “new carryon standard” stuff is just misinformation from AI generated clickbait channels on
YouTube. One of the travel channels I watch sometimes did a video debunking it.
Re: checking vs carryon. I do both. I get free checked bags on Delta and JetBlue. Never had an issue with checked luggage but I keep air tags in all my bags and clothes in the carryon for that reason. I don’t fight for bin space getting on with zone 1 and sitting in the front. But there’s too many cons to me for doing just one or the other. Carry on only I can only do for very short weekend trips, anything more than 3 days and liquids become an issue (shampoo bars do not work for my hair type). And I take meds so only checking a bag does not work.