You can move out of province at any time, but it is not recommended since it is considered misrepresentation.
At the time of PR renewal or Citizenship, you may be asked to present proof that you stayed in the province and tried to find a job in your specified NOC through which you got the PR. You will need to have documented proof of where you stayed, what jobs you applied and rejections you received.
I believe at-least 3-4 months (more is better) of paper trail is needed, else you will be tagged for misrepresentation to get a PR.