Allah will not call you to account for vain utterances of your oaths. He will hold you accountable for your deliberate and intentional oaths. If you violate such oaths, that would be a transgression against your 'Self'. The expiation for that if you have violated an oath is: Feeding ten needy persons of what is standard for your own family, or clothing them. Or, freeing one human being from bondage, whether it is slavery, extreme poverty, heavy debt, or oppression. If you do not have the means to do so, then observe Abstinence for three days, as in Ramadan. This is the expiation of your intentional oaths. But be mindful of your oaths. Allah explains His Messages, so that you might have cause to be grateful.