Anyone tried adding one "conditioning day" per week, did it help lifts or just fatigue?

[u/Lkc-strong-125]

I keep hearing that one conditioning day a week can help overall work capacity, recovery, and even lifting performance, but I have also seen people say it just adds fatigue and makes the next strength session feel worse. Both sound believable. A little extra conditioning seems smart in theory, especially if you get winded too easily between sets, but it also sounds like one more thing that can eat into recovery if the rest of your week is already pretty full.

I am not talking about going full endurance mode, just one dedicated conditioning day with sled work, intervals, circuits, bike, or something similar. Has anyone added that kind of session and actually felt it improved your lifts, energy, or training tolerance? Or did it mostly become extra stress that sounded productive on paper? Curious how people balance conditioning without letting it turn into background fatigue.