When two or more web pages of your website rank for the same keyword phrase this causes something called keyword cannibalization where your website is competing against itself. This can have a negative role on your website rankings and traffic because it will lower your CTR (click-through rate), lower the authority of your website, and as a result lower the conversation rate of your website. The best practice is to silo your content into hub pages (parent pages) and sub-categories (children pages) of your content.
A possible plus can occur from this though. You may end up ranking twice in the SERPs for the same keyword phrase which gives you more real estate in the SERPs (search engine results pages).