2-3 broken links are no more for a site but it should be removed from site, because in SEO broken links or links not found was not good if you are going to get good positions for your keywords on SERPs
Broken links are those links that bring you to a new page that says 404 errorâ€. A broken link can impact on you SERP and it cause frustration and irritation for your incoming traffic on your website. To solve out this problem install a plugin for 301 redirection where you can redirect any broken link to your new good link which may relavent to your information.
Why not just fix the links? These links are obviously pointing to content which can help... In the worst case use 301 redirect i.e. home page in order to maintain some loss of link juice... Just to add I personally use Xenu a free tool which allows you to find broken links - but what is really cool is that you can find broken links on other sites and once found you can ask the web master to replace them with a link to your site (assuming that it is relevant) and hey presto you've got a nice backlink helping you on the SERPs ;-)
Broken links can be harmful for your traffic and, in some cases, ranking as well. If you have a broken link coming to your website, then you could lose some users who were interested in visiting your website. If you get a backlink, but with a slightly incorrect url, then your website would not get that link juice.