I came across information online noting that for compounded versions, official guidance often permits 21 to 30 days at room temperature below about 86°F after first use or mixing, leading some to forgo the fridge during the in-use period. Hope that helps, though others here will likely have more insight.
My small refrigerator stopped working for two weeks without me realizing it. I still used the reconstituted product anyway. This made me wonder whether some people skip refrigeration completely after mixing.