In On Page Optimization Keyword stuff is not much important in SEO. Because nowdays google not giving more weightage to keywords. User who having unique content with more backlink they can only get good ranks in google. In SEO 30 % is about on page optimization work. 70% is off page optimization work. Google giving more precedence to off page optimization only. Based on the quality content then repeated words can be used as keywords. When google crawls your page means it will take photo copy of your page. If you search your website with the related keyword present in the content means it will easily fetch the result from the result from search engine.
Google algorthim may change frequently beacuse now the internet users are increased. More people creating therir own websites and posting in web server. Google wont fetch all websites. There is no certain period to crawl the website. Google will crawl the unique content and more back links site only. So keyword is not important in SEO part.
May be google algorithm will change in future by giving importance to Meta Keywords. I think this post will my site rank first in googlehttp://harithecreativethinker.blogspot.com