I largely concur in the observations posted by
@vasvas.
The main point warrants emphasis:
rely on the online physical presence calculator. It will calculate an EXACT number for days absent, number of days counting as present, duly taking into account credits for whole or half days as applicable.
(Note, for example, that absences after landing require an additional day of presence in Canada until, at the very least, the PR has been physically present in Canada a minimum of 730 days after landing NO matter how long the PR was in Canada before landing. But if the information is correctly entered into the online presence calculator, this is all properly calculated for the applicant, no need to do any arithmetic let alone math.)
Beyond that, some caveats and reminders:
I. The Reliable Calculation: A reliable calculation depends on (1) using the physical presence calculator, and (2) PRECISELY entering ALL exit and entry dates ACCURATELY. Also see below further reminder re getting this information right.
II. Buffer Insurance: There are TWO types of buffer insurance benefits.
1. Shortfall Protection: That is, having enough buffer to avoid being short if IRCC determines or perceives there are absences in addition to those declared in the applicant's residency calculation. (Enough to cover potential applicant mistakes or IRCC's error or CBSA travel history errors; while these, and the latter two in particular, may be unlikely, remember that insurance is not about what will happen but more about what can happen even if unusual, as some Ottawa area residents got an F-3 lesson about this last week.)
2. Non-routine processing avoidance: That is, providing enough of a margin over the minimum to reduce the risk of non-routine processing, and especially full-blown RQ, to in effect minimize the risk of lengthy delays in the processing timeline.
The first of these is about avoiding a negative outcome. Falling short results in the application being denied.
The second is about avoiding, to the extent possible, the inconvenience and delay of additional requests for proof of presence. This is about having enough over the minimum to make IRCC personnel comfortable concluding there is no reason to question or more closely examine the applicant's presence calculation or travel history.
While there are many factors to consider in deciding how long to wait, in deciding
when-is-the-right-time-to-apply? as to just the frequency of travel aspect,
a buffer of an extra day or so for each border-crossing is probably a sensible guideline. (Thus, for example, the PR who has made three or four week-long or longer trips abroad, plus a dozen day or one-night trips to the U.S., would be prudent to have a buffer of at least two to four weeks.) Other factors may suggest more (if, for example, there is any chance of overlooking a trip or even just being off on the dates of a trip, if for example the PR did not keep perfect contemporaneous record of all travel, a bigger buffer would be prudent).
III. More Regarding The Reliable Calculation:
As noted, a reliable calculation depends on (1) using the physical presence calculator, and (2) PRECISELY entering ALL exit and entry dates ACCURATELY. The importance of getting this information precisely accurate cannot be overstated.
Thus, for example, boarding an international flight scheduled to depart a Canadian airport before midnight is an exit on that date, the date before midnight, even if the flight sits on the tarmac past midnight let alone does not actually leave Canadian air space until after midnight. Similarly, the arrival date is based on the date the PR actually clears customs. It is not the time a flight enters Canadian air space, not the time the flight lands on the tarmac in Canada, and not the time the PR walks into the terminal . . . even if all those are before midnight, but if customs is not cleared until after midnight, the date of arrival is the date after midnight.
Similarly as to short road trips to the U.S. It is the date the respective border officer swipes or otherwise logs entry that counts. After midnight is the next day.
Common error: Scores and scores of citizenship applicants make the mistake of reporting exit dates based on a passport stamp showing date of entry into another country. This can be off by two days for a Trans-Pacific flight, and is off by at least one day for any red-eye or late night flight. While one or two such errors, all alone with no other errors, should not cause much of a problem, the risk of elevated scrutiny and delays will increase significantly if there are multiple such errors, or if they occur in conjunction with other mistakes.
