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It's better to use a dedicated drive for TM.
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Something about twice the size of your internal drive. Lastly, I would be inclined to use a reliable HDD (spinner) external drive, if you have one, rather than your SSD for Time Machine. With later macOS the process is a little different and TM can boot your device into the Recovery Partition but you need to use Internet Recovery to instal the OS before restoring your data because TM does not copy your Operating System like a clone does, just your user data. If you have for example an operating system 10.14.0 or before you can create a bootable clone which makes transfer to and formatting of a new blank internal drive a breeze. Most cloning software offer 30 day free, no obligation fully functional trials. It would be good to know that? Older Mac OSX have different restore process' to newer macOS. In your case it depends a little on the Mac Operating System you are running. The two have different qualities, advantages and disadvantages. Clone there is no simple answer, I use both.
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