Broken links is one of the factors which negatively influence on the quality of the website and, in its turn, website position depends on its quality in general. And what turns out? Broken links indirectly influence ranging, and respectively, the website traffic.
If today there are no broken links on the website, it does not mean that after a while they will not appear. Therefore, we recommend to check the website for broken links from time to time. The frequency of check depends on the type of your website (online store, news site, etc.) and traffic volume.