On Windows 10 I had this setup. On the main disk I had the OS, on the second disk I had all my personal files mounted with first drive (so if the OS breaks down I have my files safe), and on the third drive I had some large files, games and backups.
Since I now have switched to Ubuntu, I have Ubuntu with ext4 filesystem on my first drive, an SSD, but my other drives are still ntfs. Can I leave the other drives as ntfs or do I need to reformat them to a different file system? I can access the disks with no problem from Ubuntu. At a later date would like to transfer home to my second drive to have the same situation as before, so do I need to change the filesystem of the other three ntfs drives?