I have been looking at different IC’s recently. The first thing I do is plug them in and listen for maybe fifteen minutes, write a few notes and then remove them from my main system and put them in another system (in the basement) and let them run in 24/7 for a week. Then I reinstall them in my main system and listen and write some notes. Then I compare the notes. I’ve done this with Power, IC, Digital and speaker cables and speakers (if I can muscle downstairs 😁).
Can’t say I’ve always heard a difference, but more often than not I do.