Welcome to the Q&A Forum

I once used no-follow tags extensively. And at one time there was some encouragement from Google on the use of these tags. Recently I removed all no-follows from the main sections of my sites. The exception is our blog which runs on a WordPress platform. Use of no-follows on purely redundant content is very sensible. Generally, they should not be used to manipulate page rank. You might want to read Matt Cutts commentary on the subject: http://www.mattcutts.com/blog/pagerank-sculpting/