If you’re giving any sort of advice in a blog post that involves an industry requiring a license (such as the medical, legal, financial, etc type industries), you must have a disclaimer stating that the reader shouldn’t rely on your advice. 

If the blog itself often has posts on this subject, you should have the disclaimer in your Terms & Conditions, but it would also be wise to include that disclaimer in the post itself. 

A disclaimer also needs to be made any time payment or a free product is exchanged for the promotion of a product. This applies to social media, blog posts, amazon shop pages, etc… Even if you do not receive payment for the post, but you did receive a free product, a nice dinner, a free stay, etc…the endorsement should be disclosed.   For more info about Disclaimers, check out THIS BLOG POST.