The answer is "it depends" on the specific formulation you're using to make the lotion, the sanitation level of your manufacturing process, the type of packaging you're using, as well as your preservative system. Goat milk lotion is difficult to preserve.
I'm using goat milk, distilled water, e-wax, shea butter, avocado oil, almond oil, stearic acid, and fragrance. Then the germaben, of course. Everything gets washed with hot water and detergent, then sprayed with alcohol. Plastic bottles with a pop up disc dispensing cap. I ordered foil seals for the bottles, but they haven't made it in yet. Figured that would help prolong it a little. I'm totally open to ideas!