Honestly I’ve done mostly forgot, and with the proliferation of AI technologies and all the typos AI has read from in the training models, I bet AI isn’t always right about this either.
I usually just don’t care anymore, whether the autocorrect puts the apostrophe in or not.
I feel like that one isn’t that hard to remember because “its” stands out as a common exception to the rule for possessive singular nouns.
“It’s” is a contraction of “it is” while “its” is possessive.
Over the years, I’ve become more and more unsure on that one. I usually have excellent spelling and grammar, but it was so long ago when I learned the difference between its and it’s, that I’ve gradually assumed I’ve seen so many typos over the decades that I just couldn’t remember for sure.