OK, my ears are burning
(Wizard appears in a puff of smoke, humming "Let's Do The Timeshift Again!")
..let us know if that pans out for you.
... and hopefully it does.
is using the default setup from 'Tessa' Cinnamon, that is Linux Mint 19.1.
Clem and his Team (Clement Lefebvre - CEO & Project Leader, Linux Mint) began installing Tony George's Timeshift with LM 18.3 'Sylvia', then backported it to 18.2 and 18.1 (not sure about 18.0 'Sarah').
At that time, it was pretty much exactly as Tony designed it.
With the release of the 19 series of Mint, Clem either of his own doing, or perhaps with contributing help from Tony George, put their own stamp on Timeshift a little, making it more aggressive with "nags" to get you to set a schedule, and other small changes. These do not occur for users of Timeshift installed on other Distros. Current version is v19.01 released 20 January 2019.
Timeshift, by default, throughout its deployment in any Distro, will, if you do not tell it otherwise, setup a hidden folder in your Home folder or partition. This will be called
.timeshift - note the dot.
Within that folder are subfolders for the types of Snapshot, whether they be Daily, Boot, Weekly, whatever. Some will be empty, if no snapshots of that type have been taken. With those of a type that have been taken, their contents will have curved arrows, perhaps, indicating they are symlinked (shortcutted) to the main folder, called "snapshots".
"snapshots" contains every snapshot of every type taken (until they are deleted if an expiry time is set), and the folders are marked with Datestamp and Timestamp.
If you have just completed a fresh install of Mint 19 and upwards (19.1), when you first launch Timeshift and go through its Wizard, you will see by default it is set to Daily. There is a timing system set up by default, whereby, if you do not set it otherwise, Timeshift will take that first Daily snapshot within the first 24 hours. You will not see it running, but if you manually launch Timeshift while this process is in operation, you will receive an error message that another instance of Timeshift is running. The first snapshot will likely be as large as your system, which may be 7 - 8 GB to start with.
If you leave the computer on 24x7, and no files are changed/modified, added to nor deleted, Timeshift will examine its logs and determine not
to generate a snapshot. This answers why some people think their Timeshift may not be running properly.
So following that first, full snapshot, subsequent snapshots are incremental, which may mean they will be as small as a few dozen MB, or as large as a couple of GB if extensive updates have been performed and new software added.
That being said, I will answer some of @Shmu26
's questions directly, in my next Post, just have to attend to a couple of other Members.