How long can breastmilk sit out if not frozen or refridgerated for it to be considered bad?

4 hours. Breastmilk can sit for 4 hours at room temperature (about 66 to 72 degrees). Longer than that, it should be refrigerated or frozen.
Short time. Breastmilk can sit out at room temperature for about 4-6 hours before it needs to be refrigerated or used.