Permanent residents must have a valid permanent resident card (PR card) or permanent resident travel document (PRTD) to return to Canada by plane, train, bus or boat. Without one, you may not be able to board.   Your PR card needs to be valid when you show it. If your card expires, you will have to apply for a new one. You are still a permanent resident if your card expires.   Residency Obligation:  

• Must be present in Canada for 730 days in every five year period. It can be a combination of the following:
• Physically present in Canada
• Accompanying abroad by a Canadian Citizen Parent, spouse or common-law partner.
• Employed abroad by Canadian Business or government.
• Residing with Canadian parent, spouse or Common-law, who are being employed abroad by Canadian Business or government.
• Outside Canada work can only be considered if it is temporary, full-time and has connection with Canadian Business.

  Restrictions:

1. PR Cards can not be issued outside Canada
2. Permanent Residents outside Canada will be issued a temporary travel document to enter Canada
3. PR card gets revoked when a person ceases being a PR.