Whenever you write content consistently, you will find that you are writing on the same keywords on occasion. When this happens, a good SEO plugin like Yoast SEO will notify that you've used the keyword 3+ times already in other areas of your website.
This brings up the fact, should you be writing content over and over again on the same keyword to rank for it OR dominate the 1st page with it?
Well, it's a 2-sided coin. You CAN get multiple parts of your site and blog posts to Page 1 BUT you also will be missing out on other long tail phrases, and variation keywords that you can write on. Simply because you are talking about "WIDGET" over and over again, doesn't mean the keyword can't be made into "WIDGETS, BEST WIDGETS, CHEAP WIDGETS, BUY WIDGETS, LEARN ABOUT WIDGETS, ETC"
We find that after you've touched on a single keyword 1-2 times, you should just move onto another variation of that keyword for great diversity and ranking for similar keyword phrases.