The calendar follows the stairs
A Montréal plex is not a suburban two-storey with a mudroom. Outdoor stairs collect grit. Shared vestibules collect boots. Kitchens are often one wall. Bathrooms are often one. The right interval is the one that keeps those rooms from sliding, not a national average.
Weekly makes sense with shedding pets, kids, or a kitchen that cooks every night. Every two weeks is the usual fit for a two-adult plex that is out all day. Monthly only holds if the home is small or often empty; bathrooms will tell you if you guessed wrong.
Winter changes the floor more than the sink. Salt and slush at the door are a household habit between visits; the visit can reset the entry, it cannot live there. See salt and slush.
A seasonal deep clean is not a substitute for the calendar. It is the extra pass for baseboards and appliance interiors.
If you want a plan, start with recurring cleaning and the first-visit notes.
