I don't understand how Time Machine Works

Time Machine is not an archive. It is a backup for your most recent files. Where most recent is a function of how much space you have on the Time Machine drive.

If you delete a file, a copy will be on the Time Machine backup drive for a period of time (but not forever). But if you deleted it last year, unless you have a very large backup drive, that file will have been deleted as Time Machine recovers space for new backups.

If you are thinking you can run Time Machine, and then delete all your pictures and documents, and depend on finding them in Time Machine, then you are mistaken, and will loose that data. Or you have invested a huge amount of money in a very VERY large backup device.

Time Machine is better than a lot of backup utilities. Many backup utilities wipe out the previous backup each time they run. At least Time Machine can go back for days, weeks, and a few months. If you have enough backup storage you can go back even a year (or more, as it just depends on how much money you spend, electricity to pay for, and room taken up in your house).

If you need an archive, then get dedicated storage just for the archive. And if you do not want to loose data on the archive device, then you should have a backup running for that device.

Any data that is stored in just 1 place is data that is at risk. The ideal backup approach is 3-2-1. 3 copies of the data (the original being the first). 2 backups using different backup utilities so flaws in one utility do not affect the other. 1 copy is stored in another location (network backups are commonly used for this, but some people regularly take a copy to a distant family member's house, or a safe deposit box, or use a network backup to the cloud).

Look at it another way. You are shoving copies of your data in a closet. Eventually the closet is going to be full. You either take out some old stuff to put new in, our you take over a larger room. But eventually, you will need more than an extra room, and have to build an addition on your house. But when that fills up, you have to buy your neighbor's house to use for storage, etc... Time Machine cannot change rooms, or build additions, or buy your neighbor's house. Time Machine has to make room in the closet it has by throwing out the old stuff to make room for the new stuff.

I'm not going to restore an entire Time Machine Backup from a different computer and operating system from 7 years ago, just to get to this one file. That's insane.

Correct. You don't have to do that.

In addition to BobHarris's comprehensive advice, if you need to restore any particular backed up item ("item" meaning a file, folder, app, etc) follow these instructions: Restore items backed up with Time Machine on Mac - Apple Support. That's the only way to do it.

It cannot be overemphasized: Time Machine is a backup system. It is not an archival system. It guarantees, at an absolute minimum, one and only one complete restorable system backup of everything on the Macs (plural) it backs up. Anything more than that is "nice to have" but not guaranteed.

I think, what I really needed to learn from this is:

If I have a file that is backed up on the Time Machine and, I delete it from my computer's hard drive, is Time Machine going to eventually delete that file or keep a copy?

Yes, that is true. Time Machine has never been an archival backup solution.

The Time Machine Browse Search only looks at the files backed up on this device in the past 3 months, because those are as far back as the backups go. I have been using this device and iteration of Time Machine for almost 3 years.

How do you have multiple backup sets on the same drive? That was possible in the past, but is no longer possible, now unless you create multiple volumes.

Either way, you would need to browse the particular backup set in Time Machine in order to search it in Time Machine. You can choose other backup sets by holding down the Option key when you select the Time Machine Status Menu Item.

Back up your files with Time Machine on Mac - Apple Support (CA)

Back up your Mac with Time Machine - Apple Support (CA)

Restore your Mac from a backup - Apple Support (CA)

I think, what I really needed to learn from this is:

If I have a file that is backed up on the Time Machine and, I delete it from my computer's hard drive, is Time Machine going to eventually delete that file or keep a copy

Time Machine will eventually delete that file when it needs space for new backups. The file will remain in Time Machine backups until that time. Time Machine deletes the oldest files first when it is trying to create more room for a new backup.

But.....there are reasons why you would not want to always trust Time Machine to do this. One of them is a situation where the backup disk is basically full and you then add a lot of new data to your Mac....an operating system update, a lot of new photos or videos, etc.

In that case, you will find that Time Machine will not be able to automatically delete enough files to make room for the new backup. And, you don't want to try deleting files from a Time Machine backup manually. That can wreck the whole backup rendering it useless.

Time Machine works reasonably well if the backup disk is close to full and Time Machine is only handling small "incremental" backups. The problems come when the disk is close to full and the next backup is much larger than normal.

Before I felt like I could trust Time Machine, I physically moved files to the external HD. If I search a file saved that way, I can find easily but, Time Machine Backup, it does not appear in the search.

Time Machine will automatically back up everything on your Mac.....(unless you manually exclude files) But, it will not include or backup the data on an external drive connected to your Mac unless you manually enable that option in Time Machine settings.

No matter whether you trust Time Machine or not, you would always want to have multiple backups of your Mac and attached hard drives. For example, I back up everything using Time Machine to one drive and Carbon Copy Cloner automatically backs up everything as well to another drive.

Some users even keep offsite backups in the event of a fire or flood.

Dear Apple Inc., Be less annoyingly proprietary. Your Tech was advanced enough to be worthwhile, back when Steve Jobs was alive. I haven't had an iPhone since the 4 and don't have much reason to stick with Apple computers, since I could buy a banger PC for the same price.

It's not proprietary. It's easy. Buy Drive, Plug It in, Turn it on. Leave it alone.

For people who must manage everything, it's not the best solution. There are other third-party backup programs you can manage to your heart's content.

It would be nice if I could find files in Time Machine using the Finder Search Bar

You can. Just Browse Time Machine Backups and use the Search Bar the same way you would do in Finder.

I was not totally clear in my first post. Time Machine does backup everything, and keeps at least 1 current copy of every file (generally it has more than 1 current copy, but at least 1 of every file is on the Time Machine backup).

My work Mac is backed up via Time Machine to 1 external drive. It is backed up via SuperDuper to a 2nd external drive.

There is next to nothing personal on my work Mac, and most of my work related files are on company hosted development systems. The backups make it easy to restore my work Mac if something happens to it, or when it is replaced once every 4 years.

My personal Mac is backed via Carbon Copy Cloner to a Synology NAS. That Synology NAS is backed up to yet another Synology NAS located in a diagonally opposite side of the house 2 floors away, so that if something happens to the house, hopefully one of the Synology NAS devices will survive. I do not have sufficient home network bandwidth to do a network backup, no family members leave nearby, and I'm not going to play disk swap with a safety deposit box.

Dear Apple Inc., ...

You realize you're not addressing Apple on this site, right?

If I understand you correctly you're asking Apple to be "less proprietary" — in other words, less of what made them the most successful company on the planet, right?

Apple already tried that idea, before Steve Jobs returned to the company he founded. A previous CEO advocated "open" Macs that were less annoyingly proprietary... just as you are now advocating. The result brought the company to within about 90 days of bankruptcy.

And if you want to buy a banger PC, you know you'd be better off sending it directly to a landfill, right? Rather than doing that, why not just take the fistful of cash a cheap disposable PC costs and burn it. Fewer steps that way. But if wasted time and effort is what you're seeking, direct your comments and suggestions to Apple, here: Contact Apple. They don't use this site for that purpose.

My backup system includes:

• iCloud
• Archival storage to a QNAP NAS
• Personal computer backed up via Time Machine to a different (dedicated) QNAP NAS
• Personal computer backed up to BackBlaze Storage
• Archival NAS backed up to BackBlaze B2 storage.