Leave freshly pumped breastmilk at aircon temp for next feed or refrigerate then warm for next feed?

#firsttimemom I’m exclusively pumping, not sure if it’s ok to just leave freshly pumped breastmilk at aircon temp for baby’s next feed. Read online that room temp milk can be used up to 4 hours but best within 2 hours. Is it better to refrigerate first after pumping then warm it up when need to use? Or is it ok to just leave it outside until baby gets hungry for next feed?