For easy navigation and referencing you use website links in almost all page. And that's fine. It's a building block of usability.
But there are few cautions to follow, because while linking you transfer Pagerank to other webpages. If you do it the wrong way seo is going to suffer.
Also, make sure you don't get into link scheme while trying to get higher Pagerank.
Start by viewing 3 aspects to check your links in each webpage.
Use text most of the time and not an image inside a link. Search spiders can't read images. So, if you do so then use alt text in your image link.
Once you click a link, you feel bad to see a 404 Error page. Others also do. So, don't have links that direct to a webpage that doesn't exist.
While following black hat methods people hide real links with coding tricks. Search spiders are smart enough to find out this nuisance.
You may offer your users a webpage with links
pointing to important areas of website.
Use minimal possible amount of links and place them in order to present a clear picture of site.
If your website is not well organized or too big to easily navigate, you may use such a sitemap.
It's not about your whole website. Rather a single webpage should have a "resonable" number of links. Including all internal and external links, any webpage must not have more 100 of them. Previously, webmaster guidelines used that number, but currently they don't. Yet you can take that as a limit if you don't want to be termed as a "Link Farm."