How long does it take to break in coupling caps?

break in generally goes like:

dull and wide mono...

to exaggerated mid-high treble/mids that are blunted and gritty, that exaggerate fine detail in a blunt phasey mildly metallic way that can sound huge - soundstage wise..

to darker or calmer but cleaner, faster, leaner.. with the grit falling away and opening finer details

then finally... to a balanced warm clean final burn in condition. Whatever that may be -- for the given item. not specifically the capacitors in question.

Thank you, teo_audio.  Is pink noise to break in any good?  I did pink noise for my speakers.

pink noise is fine. Wideband is the deal. and pink noise is generally that. Ie, 20hz-20khz pink noise.

Thank you.