Handcrafted chili oil has been useful in several products I have made over the past winter season. (think soothing muscle rub, spicy lip balm or warming foot rub).
Generally, oils for infusion should have a long shelf life, although there can be benefits from using a specific oil with a specific ingredient for infusion and then using the entire batch within a short time of making it.
If you’re interested in giving this a try, there’s a chili-oil how to right here on the main blog. Depending on the strength you are looking for, vary the type and amount of chilis you work with. There is tangible difference in heat and effect depending on which ingredients you choose.