working with .aup vs .mp3

once i record and save as .aup i usually export to both .wav and mp3.
if i need to edit something after should i be using the original .aup file or the exported .wav/.mp3
does it matter of is it basically all the same?

thank you

The mp3 is certainly NOT for edition and re-edition.

I normally work with WAVs and I rarely make an AUP project, but it depends on what you’re doing. If you have multiple files or something like that, you may want to make a project.

MP3 is lossy compression. If you re-open it in Audacity (or any “normal” audio editor) it gets decompressed. If you then re-export as MP3 you are going through another generation of lossy compression, and the “damage” does accumulate. If you want MP3, compress ONCE as the last step.

AUP projects are 32-bit floating point so they are actually higher resolution than “normal” WAV files, but that usually makes no difference (in sound quality, etc.) unless your levels go over 0dB. WAV files will clip (distort) if your peaks “try” to go over 0dB. (Your “final” file shouldn’t go over 0dB anyway.)

thanks for the input

so i am concluding its probably a better practice to save the original .aup as master and make any changes going forward from the master

Audacity projects are complex, with many (sometimes thousands) of separate files.
A normal audio file is just a single file, and so is easier to handle safely. WAV and FLAC files are particularly robust. I would recommend always having a backup in either WAV or FLAC format.