The stated period shapes what dependents can plan around, since a spouse and unmarried children under 21 may seek TD in connection with the principal's arrangement. TD permits study but does not authorize employment, so a spouse's work plans need a separate basis.
Plan the household around the stated period
If the letter names an initial period with possible extension, treat leases, school enrolment, and a spouse's resignation as decisions tied to that period rather than to a hoped-for renewal. Each dependent's steps depend on their own nationality, and a child who is a US citizen does not need TD. Ask counsel how the family's applications should reference the principal's arrangement.
If the spouse maintains independent employment authorization, verify its conditions before budgeting that income. Assess the spouse’s proposed activity and lawful authorization separately from the household budget. Prepare a separate status-and-activity summary for the TN professional, spouse, and each child, noting missing passports or admission records. Self-employment in the United States is excluded, ownership in the employer must be disclosed, and dependants in TD status may study but not work. Record the children's birth dates; a child who turns 21 loses TD eligibility, and marriage ends it regardless of age.