When My Permalinks have to change

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Bruno Michalski: Hi,
  
  I have site that has been around for a few years and is pretty well positioned in google search. Now I would like to rebuild the site by introducing a framework. One of the things that framework changes is that everything is routed through index.php and urls are being rewritten.
  
  Currently subpages look like this (example):
  mysite.com/home.php
  mysite.com/work.php
  
  after the framework introduction they will look like this:
  mysite.com/home
  mysite.com/work
  
  Will this change hurt page rank or keyword hits etc. I mean since to google this may seem like new pages will it reset all the hard work site done over the years climbing to the top of search results and if so, how one can mitigate such problem (301 redirects perhaps?).
  
  Thanks in advance for any insight!
  
• 
  Federico Sasso: 301s, indeed!
• 
  jasmin jew: no .. page rank will not be effected
  
• 
  Bruno Michalski: +jasmin jew
  So you are saying that if I don't do 301s just have same pages respond to address without .php it will not hurt how site appears in google?
  
  If so can you point me to the source of that knowledge? Its crucial that nothing bad happens to search results so I would rather double and triple check :).
• 
  Rotimi Orimoloye (Orims): The pages that rank will still rank on Google search, but with their old urls. That means anyone that clicks them will see a 404 page. ;
  So, definitely 301.
  Hopefully they aren't too many. :) ;