What is the expiation for someone who swore and made vows many times not to return to a certain act, then returned to it many times?

If you swore many times not to return to a certain action and then you did return to it, you owe a single expiation (kaffarah (definition)). This expiation involves feeding ten poor persons, or clothing them, or freeing a slave. If you cannot find any of these, then you must fast for three days. This is based on the Almighty's saying: {Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what you intended in your oaths. So its expiation is the feeding of ten poor persons from the average of that which you feed your [own] families or clothing them or freeing a slave. But he who finds not [the means to do so] - then a fast of three days. That is the expiation for oaths when you have sworn. But guard your oaths.}

This applies to every oath related to a single action or abstaining from a single thing. If the oaths were repeated and you did not expiate for the first one, then a single expiation suffices. However, if you expiated for the first oath, then repeated the oath and broke it, you owe a second expiation.

The amount of food to be given is half a sa' of the staple food of the land for each poor person (approximately one and a half kilograms). The clothing should be what is sufficient for prayer. It is recommended to avoid frequent swearing and vows.