How to take a disk image of a perfect OS State with Apps, and keep it for refresh/disaster recovery purposes.

I think the fundamental difference between Time Machine and most of the others is: Most backup schemes are keeping the ONE backed up state, and that ONE is the Most-recently-saved state.

So when you need the saved state from last week, from just BEFORE you installed 'that add-on that turned out to be so horrible', most backup systems can not help you. "Sorry, that is not available separately, but we DO have late yesterday!"

What Time machine does differently is to save and keep careful track of MULTIPLE saved states. Rather than merging the incremental backup data into the ONE backup, it keeps that each incremental backup separate, identifiable, and able to be combined with the other data it already holds to obtain a Perfect image of your Mac as of, "any date&Time it still has saved".

Time machine saves:

other backups are NOT DELETED, they are consolidated, so that it can still produce perfect, accurate copies as of any date still on hand.

<< it would seem time machine overwrites the oldest back up. >>

Time machine's capabilities are much more complex than that, and far more subtle. Time machine only overwrites very old backups after it has thinned recent backups considerably, and has no more room.

If you are not overwhelming the saved data by including your project files, and you provide an adequate-sized drive, you may never experience old data deletion.

Time machine can save the "golden state" you desire from today. In addition, it saves the state from an hour ago, AND last week, AND last month. It does this by saving changes in database constructed in such a way that ANY backup still contained in its backup set can be restored, completely, in ONE step.

Time machine really shines after you have a Major OOPs, such as deleting something important you did not mean to, or installing something that made a mess, but you did not realize that impact for several days. Time machine can restore to the day before your system got screwed up. OR the week before. OR the month before.

But Time Machine's even more important feature is that it works ay low priority in the background, keeping your backups current. When you need it, Time Machine backup is the backup that got done, because you did not have to set aside a special time just for backups.

In the old days, you could use Carbon Copy Cloner or SuperDuper! to make an exact bootable clone backup. If you made a couple of backups of your "ideal system state" and set the backup drives aside, that would have done a lot of what you are looking for (modulo any DRM, a.k.a. "intentional incompatibility", hassles).

These days, Apple has locked down system security with cryptographically sealed signed system volumes and with security policies that make it difficult or undesirable to allow booting from external drives.

This complicates things, as explained on some of the blog entries / articles on the CCC site. You can still use CCC to make bootable clone backups (of a sort), but the default is now just to make a non-bootable clone backup of your data. With the idea being, I guess, that you reinstall the OS using Internet Recovery if something happens.

+1 on CCC!