Internal Links in Header Bar

Is it worth adding links to posts that are already in the header bar? Obviously you should where it is navigationally appropriate, but is there any extra juice for (intelligently) putting it on high performing pages where there may not be as obvious of a placement?

When you are doing posts and content creation think more about User Experience more than internal link juice.
High performing pages pass link juice because they pass traffic. Traffic is king.
Write pages such that it keeps people on your site.
So, internal link as much as you can without being pushy or distracting while still allowing people to explore your site.

So, if the question is: Should you link to a big category even if the link already exists in the Header Bar?
Answer: Yes, as long as it makes sense for the content and will keep people moving through your site.

Foodie Blog Example: The Header Bar may have a "Recipies" category, but you can still link to the "Recipies" page at the bottom of a post if you want to say something like "Explore all of our other Recipies here!" That is logical and smart.

I agree what @Jetblack101 said

If your site structure doesn't hurt so it will be good practice.

I see no downside to doing so, as long as it doesn’t mess with the structure or visual identity of your website. You want as much traffic as possible, and interlinking your site will increase your traffic. So, if you can pull it off without a cost in appearance or user experience, go right on ahead and do it.

You gotta have a strict plan for your internal linking. It's not about adding links to the header or not, but to decide how you'll structure your internal links.

Research about in-page SEO and see link structures. Silo, etc.