You're required to be present 2 out of every 5 year period; you can be outside Canada for 2 years straight or more, just e sure that for a period of 5 years, you're present in Canada for 2 to maintain your PR status.
Another way of looking at it would be that you could stay out of Canada until Jan 2019 but then would need to stay in Canada for 2 years without leaving in order to keep PR. Also keep in mind any residency requirements for citizenship if that is ultimate goal http://www.cic.gc.ca/english/citizenship/become-eligibility.asp#time
You're required to be present 2 out of every 5 year period; you can be outside Canada for 2 years straight or more, just e sure that for a period of 5 years, you're present in Canada for 2 to maintain your PR status.
You're required to be present 2 out of every 5 year period; you can be outside Canada for 2 years straight or more, just e sure that for a period of 5 years, you're present in Canada for 2 to maintain your PR status.