When to Dither / when not to ?

[Enzo]

Yes I've done a search - NO Im none the wiser?

OK - here it is: I always record at 24bit ~41 /

NOW; I have one session in ProTools that has parts from different studios - I have one instrumental track at 16 bit ~41 / I have one sample track at 16 bit ~48 / and all my parts are at 24 bit 41...

Which parts should I be dithering where? /The overall session spec that I want to work in, is 24bit ~41..

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SO.... One guy said I should be opening up each sound file in its own session at the same spec as the file in question (so he means - open up the 16bit 48/ file in a session with a spec of 16bit 48)/ then bounce that file, dithered at the same spec as my target.. (always 24bit ~41)/ so when I open up the new 'dithered' file, it will sound better matched with what I'M doing (which is always 24bit ~41 as I said earlier) - BUT this would mean bloody files dithered all over the show, and then dithered once again at master output / bounce! That can't be right or good.. HELP?!

Surely you don't have to dither EVERY time you change a file from one spec to another, do you?