Link(v.), only when it’s absolutely necessary, especially on your premier pages (landing pages from search engines) that have a touching relation with the sales. Every offsite link you make on the page, and even onsite links to other pages, dilutes the theme you intend to rank for in search engines, thus effectively bringing down the performance of targeted terms.
When you have to link, however, make sure that the linked page is as relevant as possible with the linking page. While doing a deep optimization of certain pages, reducing the number of irrelevant links on those pages as many as possible is definitely a good idea. Therefore, you should deflate the site navigation as well as other unnecessary link spots as thin as possible and construct vertical linking structures for each targeted theme while maintaining a site-wide theme that’s more general in niche.
By vertical linking structure, or siloing, I mean within each of the more specifically targeted themes under the site theme, you will link similar pages together but avoid cross-linking among themes targeted for different terms, even if they are related to each other.