How does Time Machine work with Mac mini?

Do not try to migrate everything. There will be loads of rubbish on your old iMac.

Where possible try to download new versions of your apps.

Just copy things on an "as and when needed" basis.

Either get the files you need on a USB hard drive and copy them to the M2 or use Air Drop which will very quickly copy from one Mac to another through the ether.

Don't be in a rush. This is a chance to make a fresh start and you don't want to fill up your SSD with accumulated garbage from the old machine.

This is the way. I’ve used this as my migration path ever since Apple abandoned FireWire.

Connect your old iMac's Time Backup to the new Mac mini during the initial setup and migrate from it.

see > Transfer to a new Mac with Migration Assistant - Apple Support

Actually I've been a little bit of a cheater the last few times I migrated. Instead of migrating from my slower Time Machine backup on an external HDD, I migrated from a CarbonCopyCloner clone on an external SSD. Worked wonders and cut the migration time for +300GB down to just under a hour.

I agree with @Ian R. Brown. Having a computer for that long of a time you will definitely have accumulated a ton of stuff, good and bad.

I would not bother with migration with that old a machine. Install fresh new up to date apps that you always use as there is in all likely hood there may be most of the apps on the old machine that simply will not work on the new machine. Also, you likely have a lot of apps you never even use anymore.

As far as data, put on the new machine what you really need and use most often and leave the rest on external drives.

As for Time Machine backups, if the drive you are using is more than 6 or 7 years old, purchase a new one and start a fresh new backup with the new system. With drives that old, it is not a matter of if it will fail but when. The backup device should be the most reliable part of any system.

alamden wrote:

... I've read that Migration Assistant is not a good idea and it is best to do a standard startup of the M2 Mini and then use another Apple Program to transfer data.

It appears that you have allowed yourself to become misled. Migration Assistant (and its predecessor Setup Assistant) is the way I have populated every replacement Mac I have ever owned.

Prior to OS X there was a similar method; though I believe it was also called Setup Assistant. This goes back to the mid 1990s.

Apple thinks about these things.