Once I become a permanent resident of Canada, do I have to stay in Canada forever?

Permanent residents are required to spend at least 730 days (two years) in every five year period in Canada. However, time spent abroad in the following cases will be treated as time spent in Canada; outside Canada, accompanying a Canadian citizen, who is their spouse or common-law partner; outside Canada, employed on a full-time basis by a Canadian business; or outside Canada, accompanying a permanent resident who is their spouse or common-law partner who is employed on a full-time basis by a Canadian business.