In my listening experience, component break-in is a real thing. I sent my Krell K300i back to the factory for service and upon return it sounded like crap. Tight, recessed midrange, no bass slam, rolled off/squeeky highs. Yuk. I just let it play at low volume for 3 days while we were out. Came back and my old Krell sound was back. Beautiful.
I had exactly the same experience with my NAD M33, Tubadour IIISE, Innuos Zen Mini Mk3, etc. all have benefitted significantly from a short break-in.
So, to the OP’s original question…. I try to wait and only change one thing at a time, but sometimes, I’m impatient. It happens and I’m OK with that.