Keeping the number of internal links on your front page as low as possible is essential for the performance of your web site. On the other hand, the number of external links is important for your SEO ranking.
You can check both the external and internal links in your pages through a website like the following one:
If you are using Linux you can execute the following command in the terminal to find the number of internal and external links:
lynx –dump yourwebsite.com
yourwebsite.com is your domain name.
Bear in mind that lynx may not be included by default in your Linux distribution and it may need to be installed additionally.