Almond milk will last for about 3 days in the fridge. It will separate on standing so stir or shake it prior to use. If you wish to drink the milk, I recommend that you blitz one or two dates with the almonds. You can also add vanilla or spices if you desire. Soak the almonds for up to 48 hours. If it is hot, soak the almonds in the fridge so they don't go funky. If you have forgotten to soak your almonds, make your milk anyway. It will still work, the end result may just be slightly less creamy.