Olive oil turns rancid and loses its beneficial qualities when exposed to excessive light, heat, and air- I also take care to keep out moisture. If it's awkward to keep a large container of oil in a cool, dark cupboard, or if you buy a large container but aren't likely to use it up in a few months, try decanting portions into glass canning jars (fill 'em, and use metal lids with protective coating.) and refrigerating it. You can take out one jar at a time to keep in the pantry, or you can also just spoon out what you need when you need it. Only the best extra virgin olive oils should not be refrigerated.

Another potential advantage to keeping it in smaller jars- you could infuse a couple of small portions with different herbs. In that case refrigeration is usually advised. Gently heating the oil and washed-but-air-dried fresh herbs or using dried herbs reduces the likelihood of spoilage from moisture. I prefer to strain out the herbs after a few days unless I want them in the dish I'm preparing, leaving me with infused oil, ready to use. I imagine you could also freeze the infused oil/herbs in ice cube trays, as I do various kinds of pesto, then store it in well-sealed zip bags in the freezer.

Good luck with the potluck!