I am almost 100% sure about the exit and entry dates to Canada since I have all the exit/entry stamps on my passport from my home country.
As others have observed, applicants who are confident that they have kept complete and accurate records as to the dates they left and returned to Canada, do not need to obtain the CBSA travel history.
In item 14.b, which is where the applicant gives consent to CBSA to disclose the details about the applicant's history of travel to IRCC, the current version of the application form, similar to previous versions, also states:
"Please do not contact the CBSA to request your history of travel."
This is not a mandate. It is a request. Applicants who have accurate and complete records of their travel do not need to obtain this redundant information, which, it must be noted, is not necessarily complete . . . it is almost always accurate, as to the history it shows, but it does not necessarily capture every border crossing. In contrast, of course, the applicant's obligation is to report each and every exit from and entry into Canada.
Reference to potentially incomplete records of border crossing events brings up the exit and entry stamps in a person's passport.
These days scores and scores of PRs enter Canada without getting their passport stamped. In particular, Canadian entry stamps document those dates as specific dates the PR entered Canada but have virtually NO weight at all in regards to whether the PR traveled on other dates, whether there were other dates of entry.
Exit and entry stamps from other countries do not show anything at all about dates a person left or returned to Canada. They can corroborate your records, help refresh your memory, and otherwise be consistent with your testimonial account of travel dates, but of course on their face they only show you were abroad on those days, and you were exiting or entering a country other than Canada on those dates.
If you have a clear, confident memory that the home country exit/entry stamps completely evidence EVERY trip you made abroad, then at least you can be certain to cover every trip (which is hugely important), and your flight-records should help to reconstruct actual dates of departure and arrival. But of course for many of those trips it is very likely the date of those stamps is not the date you left or returned to Canada, unless on every trip you made, going both ways, you landed and cleared the entry procedure on the same calendar day the flight departed. From so-called red eye flights and other reasons why the trip goes past midnight (such as layovers for connecting flights), to west bound trans-Pacific flights (for which it will always be at least a day later than the day the flight departed Canada), many times the other-country stamp is a day or sometimes two days off from the date the PR left or returned to Canada. One or two mistakes related to this should be no problem, but of course the best approach is to make no mistakes, and more than a couple dates off can cast doubts on how reliable the applicant's report of travel is in other respects (compromised credibility is not a good place to go).
The more certain you are that you disclosed EVERY trip AND got all the actual Canadian departure and entry dates accurate, the more comfortable you can feel about a margin of thirty or so days above the minimum required presence. There are other considerations, particularly for those who hope to avoid non-routine processing, but in terms of assuring yourself the application will be successful, a margin which will for sure comfortably cover any possible omission or error should easily work. (No margin is required. A margin is about assuring oneself of success in the event of an error, and to some extent about helping IRCC processing agents feel comfortable about not asking for more evidence or proof of presence in Canada.)
