A weekly plan maintains a consistently high level of cleanliness and suits homes with a lot of daily activity: children, pets, or working from home. The short gap between visits prevents dirt from building up.
A biweekly plan suits smaller homes, or occupants who keep up with routine cleaning themselves between visits and prefer to focus the professional cleaning on the thorough work: floors, windows, and bathrooms.
There's no single right answer: it's worth starting with one plan and adjusting based on the results you actually see at home.