That's a good question and I'm glad you asked it. Pretty much whenever I come across something new - some weeks every day, some weeks one day only. I post to the blog weekly (at least). The "What's new?" page will tell you. You can also sign up there to be notified directly.
Another good question. It's as up-to-date and accurate as I can make it. But everything human has flaws (at least that's my excuse) and there are undoubtedly mistakes on the site. Let me know of any you come across and I'll correct them immediately.
I've disabled WordPress registration on the blog section because of suddenly huge numbers of Ukrainians with a passionate interest in Irish genealogy. If you subscribe in any shape or form and tick the "contact me" box, you'll get notifications of blog posts long after your subscription expires. So the short answer is "No, but ...".