Remove unnecessary backups from TimeMachine to get space I know that oldest backups are removed automatically when there is no space for new ones on TimeMachine. I use TimeCapsule also for sharing files on WiFi, so I’d like to free some space by removing of unnecessary backups: 


Large files which needen’t to be backed up (e. g. image previews of Lightroom over 1 GB). I have excluded them in TM preferences but they are already present in older backups keeping space forever. 
Oldest backups I know I will not need. (So to trigger the same as TimeMachine does automatically but earlier than disk gets empty).
You can simply enter Time Machine and select folders, apps, and files and select to delete all backup copies of that item. The command line tmutil compare also gives exhaustive detail of what changed between backup intervals if you don't mind using the terminal and a UNIX shell. Even without shell tools, you can micromanage storage from the Time Machine GUI as follows - quoting Apple's article on Mac Basics: Time Machine:


  You can also enter the Time Machine restore interface and find files that can be removed from the backup drive itself to conserve space. To do this, select the file(s) and from the Action pop-up menu (gear icon) in the Time Machine Finder window choose "Delete All Backups of...". Be sure to only delete files you are sure you won't need or want to restore later.


Next, you can use a tool like BackupLoupe to analyze your Time Machine backups to identify how much space each interval used, how much space your average backup takes, how long it will be to fill the drive at the current rate, etc…



With that level of detail, you can curate your storage needs as little or with as much detail as the situation requires. This tool has helped me figure out problematic backup drives, Macs with filesystem corruption (when each backup is larger than it should, etc…) Once you have visibility on what's being stored, you can delete folders, entire snapshots and configure your backup exclusion lists to be in harmony with your available storage and backup needs.