Timeshift is great at least in theory. Haven't had to use it, thankfully.
I want to know if there is a way to limit the number of snapshots in keeps to prevent my hard disk from being filled unnecessarily.
Right now I have 2 daily backups set in timeshift and of course it creates snapshots during update etc which is excellent.
sudo micro /etc/timeshift-autosnap.conf
default is three, I use five.
You do not need to change the timeshift settings for daily, weekly and so on.
Uncheck all.
maxSnapshots=5
Gonna change it to 2. Thanks a lot.
I update my system more than three times a day, so I need min. 5 snapshots to be on safe side 
I usually only do it once. 
But if you're using BTRFS doesn't that already avoid filling your hard disk unnecessarily? With BTRFS being copy-on-write and all? The only things save would be the files you changed with the update.