Visitors may no longer be granted 180 days’ stay in Mexico by default; instead visitors are granted a number of days commensurate with their intentions and immigration officials may ask for supporting evidence of those intentions.

How does one provide supporting evidence for one's intentions to sit on one's ass in the sun, on the beach with a beer?

There are two other threads about this topic, but the titles of the threads are not very descriptive, so I’m starting this one. Here is some information from another website.

https://www.mexperience.com/changes-to-time-allowed-in-mexico-using-a-visitor-permit/

The way visitors are admitted to Mexico is changing in regard to the amount of time granted to stay under auspice of a visitor permit (FMM)

Mexico’s visitor permit (FMM) allows visitors to remain in Mexico for a maximum of 180 days but the number of days granted has always been at the discretion of the immigration official at the port of entry

Visitors may no longer be granted 180 days’ stay in Mexico by default; instead visitors are granted a number of days commensurate with their intentions and immigration officials may ask for supporting evidence of those intentions.

The decision about how many days are granted remains at the discretion of the immigration official at the port of entry and the number of days granted (written) on the permit is the maximum time you are allowed to stay in Mexico: it will never exceed 180 days, but it may be less than 180 days.

Visitor permits (FMM) cannot be extended or renewed;

You must leave Mexico before your visitor permit expires.

What this change means for visitors to Mexico

If you are visiting Mexico under the auspice of a visitor permit this change to the way visitors are admitted might or might not affect you. If you intend to stay longer than a couple of weeks, then you should explain this to the immigration official who will ask about your intentions and may ask to see evidence in support of your plans; for example, accommodation arrangements and return flights.

There is more information at the link I provided.

Thank you, but I believe the most reliable info is still found on the government's website in Spanish. The KEY is to explain yourself clearly at Migración so that there aren't any obvious errors such as people receiving 20 days when they plan to be here for several months.

https://www.mexperience.com/changes-to-time-allowed-in-mexico-using-a-visitor-permit/

The way visitors are admitted to Mexico is changing in regard to the amount of time granted to stay under auspice of a visitor permit (FMM)

Mexico’s visitor permit (FMM) allows visitors to remain in Mexico for a maximum of 180 days but the number of days granted has always been at the discretion of the immigration official at the port of entry

Visitors may no longer be granted 180 days’ stay in Mexico by default; instead visitors are granted a number of days commensurate with their intentions and immigration officials may ask for supporting evidence of those intentions.

The decision about how many days are granted remains at the discretion of the immigration official at the port of entry and the number of days granted (written) on the permit is the maximum time you are allowed to stay in Mexico: it will never exceed 180 days, but it may be less than 180 days.

Visitor permits (FMM) cannot be extended or renewed;

You must leave Mexico before your visitor permit expires.

What this change means for visitors to Mexico

If you are visiting Mexico under the auspice of a visitor permit this change to the way visitors are admitted might or might not affect you. If you intend to stay longer than a couple of weeks, then you should explain this to the immigration official who will ask about your intentions and may ask to see evidence in support of your plans; for example, accommodation arrangements and return flights.

There is more information at the link I provided.