My opinion should be taken as that, an opinion. But know this: I have played around with internal linking for four years, and my views on this subject are because of it.
Internal linking comes down to a couple factors: relevance, and SEO value. We’ve learned that sitewide links can be unnatural, and actually hurt your SEO.
When you write a new blog post, you’ll undoubtedly overlap in subjects with something you’ve written in the past. Linking to the other post will allow the user to click though to your other post and get added value from your site. The longer a visitor stays on your site, the better, so these relevant links ARE good for SEO. You can overdo it with internal links, but I wouldn’t put a specific number on how many to put into each post – just make them natural and relevant!
Putting too much thought into anchor text for internal links can put you in a hole from which it’s hard to get out. For example, if you landed yourself a Google Penalty, which can cripple your site, you might not know exactly what caused it. Should you go through and change up every single instance of an exact-match anchor text? This would be tedious, and might not even get the penalty removed!
The internal link debate isn’t much of a debate to me – I choose to create relevant internal links to any page that might benefit the user. Anchor text plays a factor, but pretending like its the end-all-be-all creates something unnatural within your site, which means you’re always bracing yourself from the next algorithm update.
Don’t live like that.