Renewing MX FMM from Guatemala by bus any advice?

You should have nothing to worry about. Just fill out the application and pay your $30 dollars or whatever it is  and they will give you a new FMM. It will be good for 6 months. The 7 day one is if you don't pay anything.

When was the last time you did a visa run? The system has changed I've heard. Lots of people being asked if they're living in Mexico after the aduanas read their travel background on the computers using  the new system that gives them further insight into the travel histories of the travelers arriving. The last time I arrived in Mexico City last April, an inspector asked me, "how many months do you want this time?" with a frustration in his tone. If you enter through Mexico City, you definitely can't pass cash to anyone. I believe the tourist visa angle is up.

Oldladyman wrote:

When was the last time you did a visa run? The system has changed I've heard. Lots of people being asked if they're living in Mexico after the aduanas read their travel background on the computers using  the new system that gives them further insight into the travel histories of the travelers arriving. The last time I arrived in Mexico City last April, an inspector asked me, "how many months do you want this time?" with a frustration in his tone. If you enter through Mexico City, you definitely can't pass cash to anyone. I believe the tourist visa angle is up.

Well I spoke with my neighbor about it,and she said you should have no problem because the visa is good for 6 months and that's the law. It does not matter how often you come.
Oh also my neighbor? She's the one that gives the 6 months visas to the tourists.