The root of the status is "enrolled full-time": a leave, a withdrawal, or a gap while you transfer all mean you cannot work

Whether you can work depends on whether you are in full-time study right now. The moment you take a leave, withdraw, get expelled, or are not in class during a transfer, the right to work is gone on the spot. If you keep working then, that is illegal work. A visa that has not expired does not mean you can still work.

Cost

No cost. Before you stop classes, take a leave, or change schools, go to the school's international student office and get a clear answer on your status.

Benefit

Canada states in writing that you may not work off campus during an approved leave. If you are not studying during a transfer, you may not work off campus either. You can start working again only after you resume your studies. On-campus work in the United States is only for F-1 students whose status in SEVIS is Active. SEVIS is the U.S. record system for international students. Active means enrolled and valid. Those students must also keep a full-time course load. In the United Kingdom, permission to work is given by course type. A part-time course does not allow work.

Notes

If the course load is heavy and you want to drop classes, ask first how far you can drop before you no longer count as full-time. That fails sooner than the work rules. In the United States, if the school terminates your SEVIS record because you broke the status rules, there is no grace period. You either apply to have the status restored, or you leave at once. If an early withdrawal is approved, you have 15 days to leave. The rules in the other 3 countries differ. Check the immigration page for the country you are in. Do not wait for the school to send a formal letter before you act.

Sources · 4

1. IRCC. Work off campus as an international student. canada.ca/en/immigration-refugees-citizenship…
2. U.S. Department of Homeland Security, Study in the States. Working in the United States. studyinthestates.dhs.gov/students/work/workin…
3. U.S. ICE SEVP, SEVIS Help Hub. Terminate a Student. studyinthestates.dhs.gov/sevis-help-hub/stude…
4. UK Home Office. Immigration Rules Appendix Student（ST26.1）. gov.uk/guidance/immigration-rules/immigration…