I am usually blogging about programming issues in my blog. Occasionally I like to write guest post in the travel category. I like to link the post from my blog as Other interest. Both are entirely different categories. Should I give the rel=nofollow to those links?
Should other interest outbound link be nofollow?
blog;nofollow
Even if categories are different, I think you shouldn't add the rel=nofollow attribute to your links. As you said, you like to link the post from your blog, thus it's a natural link and search engines like natural links.