How do I prove how many days I spent in a country?
With records made at the time, not with a reconstruction. Travel bookings and boarding passes, immigration entry records, expense claims carrying a date and a place, and calendar entries all exist for reasons other than tax, and that is what gives them weight. The test an examiner applies is whether a count can be traced to a source. A schedule that simply asserts totals invites the authority to substitute a count of its own. Keep the sources themselves rather than only the summary, because the summary is worth no more than what stands behind it, and where two sources disagree, settle it in writing while the year is still open.
Can I use my phone or my calendar as evidence of travel days?
As part of the picture, yes. A calendar shows intention and a device shows where the device was; neither on its own establishes where the person was. Both become useful when they are set against something independent — a flight booking, a hotel folio, a card transaction in the same city — so the sources corroborate one another. Device records carry a further limitation worth knowing before you rely on them: they are generally retained for a limited window and then overwritten, so the material exists while the year is open and not afterwards. If you intend to lean on them, export them on a regular cycle rather than at the moment you need them.
Does a part day count as a day present?
It depends which test you are applying, which is the reason to record arrival and departure times rather than dates alone. Residency tests, treaty conditions, provincial and state rules and social security certificates each define presence in their own terms: one may count any part of a day, another may disregard a day spent in transit, another may look to where the night was spent. A single day count therefore cannot satisfy every test at once. Record the underlying facts — arrival, departure, the purpose of the trip, where each night was spent — and derive each test's count from those, so one travel record answers all of them.
We never tracked days last year — can it still be reconstructed?
Usually something can be rebuilt, and it is rarely as good as a record made at the time. Corporate travel systems, card statements, roaming records, email metadata and immigration entry records can between them produce a defensible skeleton of a closed year. What is normally lost is the detail the tests actually turn on: whether a day was transit, where the night was spent, whether the trip was for the employer. Expect the gaps to be resolved conservatively, because a day nobody can evidence generally has to be assumed against you. Then put a quarterly reconciliation in place so this is the last year anyone has to rebuild.
Do social security certificates need day records too?
Yes, and they are often where a weak record is first noticed. A certificate that keeps an employee in their home scheme while they work in another country is granted on stated facts: the period, the destination and the pattern of work. If the actual pattern drifts from what was applied for — longer, more countries, a different entity bearing the cost of the employment — the certificate may not cover the period it appears to cover, and contributions can be claimed in both systems for the same work. Keep the itinerary that supported each application with the certificate, and check the position when a posting is extended rather than when it ends.
Who should own day tracking, HR, payroll or tax?
One named owner, whoever it is, with a fixed date each quarter for closing the count. Presence data arrives from travel bookers, expense systems, managers and the employees themselves, and with nobody accountable it accumulates in four places and reconciles in none. In practice the owner is usually mobility or payroll, with tax setting what has to be captured for each country in scope. Make the deliverable a closed quarterly count per employee per country, signed off by someone, rather than a live spreadsheet nobody signs. The point of the ownership is evidential: an ever-changing file is worth less than a modest count that was closed on a date.
What is double tax relief and how is it given?
Three mechanisms, and which one you get depends on your residence country's law and the treaty. Exemption leaves the foreign income out of the residence-country base. Credit taxes it and then subtracts the foreign tax, capped at the residence-country tax on that income. Deduction merely reduces taxable income by the foreign tax, and is usually the weakest. Canada and the United States lead with credit; several treaties give exemption for specific income types. See claiming the credit.
How does the treaty tie-breaker work when both countries say I am resident?
As a sequence, stopping at the first test that gives an answer: where you have a permanent home available; if in both or neither, where your centre of vital interests is; then habitual abode; then nationality; and if all of those tie, the two tax authorities decide by agreement. It is evidential rather than elective — you do not choose your treaty residence, you demonstrate it, which makes the record of homes, family and time the substance of the claim. See tie-breaking dual residency.
