SHORT ANSWERS
MASTERING
Can online mastering be professional?
How long does it take to master an album (CD)?
Is it worth mastering a song for youtube, Spotify, iTunes, etc.?
Is your mastering radio-ready?
Can you change things in the mastered tracks if I don't like them?
I don't do CDs anymore. Can you work in DVD quality?
TECHNICAL
Is 24-bit better than 16-bit?
Should I record and mix in 24-bit?
Peaks higher than 'O' can be corrected later in a mix?
Is it a must to use compressors?
Do you use multi-band compressors for mastering?
Is it beneficial to mix to 24-bit if my tracks are in 16-bit?
Should I record and mix in a higher sampling rate than 44.1 kHz?