Treat it as a planning objective while eligibility, evidence and the correct procedure are worked through. TN preparation and the government's actual decision are separate steps, and an expected date is not itself authorization to begin work.
Track what still needs to be confirmed
Identify what the employer still needs to finalize and who controls that information. Canadian citizens may apply for TN classification at a port of entry or through an employer-filed Form I-129, and they generally do not need a TN visa stamp. Review current border procedures before booking non-refundable travel. If the position, employer or duties change before the trip, have the revised facts reassessed rather than assuming the original review still applies.
Turn the target start date into a sequence of dependencies: settled duties, completed employer letter, credential availability, procedure choice, and travel date. Give each dependency an owner and a date for confirmation, then revisit the sequence if the job changes. Hypothetical example: an architectural-acoustics analyst is promised a July start, but the employer has not decided whether the analyst will serve one client or several. The employer should resolve that fact before the applicant relies on the date or books travel. Canadian applicants commonly request TN classification during inspection, while an employer can instead pursue a USCIS petition using Form I-129. Neither path permits the applicant to use TN as a vehicle for operating a personally controlled U.S. enterprise.