B2 Visa: Minimum time between two stays

Hello, I’d like to hear from travelers (French nationals) who have a B2 visa (tourism) about their experiences. I read on the U.S. Embassy in France’s website that the B2 visa allows travel for up to 6 months (at the discretion of the immigration officer) within U.S. territory. It’s possible to renew the stay multiple times during the visa’s validity period.

If I understand correctly, I must leave the U.S. BEFORE the date stamped in my passport (or on the I-94 form) by the immigration officer upon entry.

What’s the minimum amount of time I should wait between two stays?

If I land in Washington (USA), travel to Halifax (Canada), stay in Canada until Calgary (Canada), visit Alaska (USA) for 2 months, and then re-enter the U.S. a few weeks later via Canada—how are "stays" and days counted?

I can’t find any official documents explaining how this counting works. From what I’ve heard from recent travelers, practices have changed in recent years. Is the counting left to the discretion of the immigration officer, or is there something less arbitrary I can rely on?

Thanks to anyone who can answer this question.

Hi there, Leaving the U.S. for Canada or Mexico doesn’t reset the clock. So the 6 months count from your first entry date into the United States. This applies to both a visa and the ESTA.