About 200-300 MB per album CD when ripped to FLAC.
About 4-8 GB per disc, averaging 5.6 GB per movie as ISO.
About 20-50 GB per disc, averaging 37 GB per movie as ISO.
I got a Verbatim external USB Blu-ray writer for about 120€.
abcde claims to rip and compress to FLAC and tag automatically.
Use dd to rip DVD. However, dd can fail on some disks, perhaps due to damage or copy protection.
This post on unix.stackexchange describes a trick that works:
For playback, most software (including Kodi and VLC for Android) can play back DVD ISO with full menu support
FindVUK has the keys to play Blu-ray discs ripped with dd.
However, with encrypted Blu-ray discs, you need to configure the keys in each device where you want to play back the content. (And this is not easy or possible in some cases.)
blu-save can remove the encryption.
Remember to specify the path to the keys when running blu-save.
However, VLC is confused by the AACS and CERTIFICATE directories that blu-save copies to the output. If you remove them, then VLC can play the BDMV directory with menus, etc.
You can repack a Blu-ray extracted with blu-save by running a command like:
mkisofs -allow-limited-size -o .../my.iso .
from the directory that contains *only* the BDMV directory.
VLC for desktop computers can open a repacked Blu-ray ISO and show the menus. Kodi for Android can open a repacked Blu-ray ISO and identify the titles. However, Kodi did not support the menus for the Blu-ray I tested.