How do I use Time Machine properly to sync two computers?

+1👍

I would never use Time Machine for "synchronizing" files across two Macs. That's not what TM was designed for and I would expect it to cause difficulties when used that way.

I suggest using CarbonCopyCloner to copy/backup your data to an external drive and swap that between the two Macs.

And, when you say "our computer data only" are you talking about everything in your user home folder or something else? The user home folder contains a lot more than just ordinary files & documents that most people think of as their data.

FWIW, I would not use Time Machine to synchronize data on two computers. I would use iCloud or another online synchronization tool to synchronize files between two or more devices. Or, you could use another external ssd and before going to your summer place copy all the files you want to the device then connect the device to your second computer.

Reformat the Time Machine Backup Drive and start over using the computer with the Most Current Data

While you are at it and perhaps it was a reversal of numbers which does happen " OS Monterey, 12.5.7 "

The current Monterey is now Monterey 12.7.5

Erase and reformat a storage device in Disk Utility on Mac

If your new Mac inherits your backup history

KenZakreski wrote:

Thank you kind stranger.

Inherit the Time Machine migration. Awesome.

But cannot the first machine inherit the new data back from the second machine?

Yes i mis wrote the current version of Monterey. Been away from tech support too long. Sorry for the error.

I think one ( you ) are making things more completed for themselves

Make a TM Backup on whatever machine ( # 1 or #2 )

Restore the Home Folder ( User Account folder ) on whatever machine

Do Not Allow TM Backup Utility to Inherit the backup on either of the machines

PS - Apple released a Monterey 12.7.6 update on Monday July 29, 2024

There is also a Safari update

About the security content of macOS Monterey 12.7.6

About the security content of Safari 17.6

KenZakreski wrote:

One year, i forget what OS, i was asked if i wanted to have the TM back up owned by the second computer. That saved the erase and rebackup. Would be nice to have that feature in Time Machine

This is exactly what If your new Mac inherits your backup history is designed to do

Once done, through the users choice, knowingly or unknowingly, Time Machine Backups on the machine that has inherited ownership of the Backups are no longer available to the Other computer.

The only way around this is not to do it next time

The other two suggestions above would be a cleaner method to Sync in the more accurate sense of Sync

Sync would only reflect onto to Other Computer the changes that were performed on the Original Computer

Using a Cloning Software is also a good idea

Though, that same Cloning Software can also be used much like Time Machine Backup with addition features

https://bombich.com/

Creating a Bootable Clone, again with that same software - the developer is not so big on this, especially as it relates to Apple Silicon Machines ( your are not )