Macworld reader David wonders whether a drive used for Time Machine backups can also store other files, or whether that could cause problems. The good news is that you don't have to devote an entire drive to Time Machine backups, although you may certainly choose to do so.
macOS writes all the archived files related to Time Machine to locations within a folder called Backups.backupdb. Everything else on the drive gets ignored. However, as a drive fills up, Time Machine starts deleting the oldest snapshots, which are retained starting seven days after an initial hourly backup as weekly snapshots.
