I keep my main collection in source format (preferably flac), then transcode it down to mp3 or opus depending on my target (eg. my phone can handle opus but my

I keep my main collection in source format (preferably flac), then transcode it down to mp3 or opus depending on my target (eg. my phone can handle opus but my ancient USB mp3 player can't). In particular, it's important that I can use opus on my phone because I want to fit as many songs as possible, and by my own personal listen tests, I need to double the bitrate for an mp3 to sound as good as an opus (though granted that wasn't blind tested or anything).