Blog Post UPdated date, Change the date or do nothing? What do you do on your blog?

Hi all, just wondering when you update a blog do you leave the original blog post date or change it to the date you've updated?

I have seen on blogs where they have BOTH 'Originally published' and 'Updated" dates but I can't see a way to do this in Squarespace.

So interested to hear what others are doing!