Should I use a different description and page title for each page on a site? it seems to me that using the same tags for each page could contribute to duplicate content a bit - what do you think?
Absolutely use different titles and descriptions for each page. In my experience, title tags are of the utmost importance. Descriptions will draw your visitors to click to your site, so create descriptions that most aptly fit each page's content. Good luck!
If you ask me, I would say you need to change the title of every page so it goes along. You don't need something like "Home page" on your 2nd page of the website. I hope you get my drift. I use wordpress, and if you do to, just grab all in one seo or something like that to change the title of every page to the title of the post, and believe me, this does help. Also add tags to it. Also, I have used the same keyword tags on every page of my websites, and I haven't seen anything wrong with it. Doing the above got my anime site to the 1st page of google, with, ofcourse, a bit of other seo work.