How are expiations paid for repeated oaths concerning ablution (wudu') and prayer (salat)? Is an expiation paid for each oath, or a single expiation for all of them?

We advise you to ignore these whisperings (waswas) and not pay attention to them, and to struggle against yourself to abandon them without resorting to an oath. An expiation for an oath (kaffarat yamin) is required for every oath that is broken. If the oath is repeated concerning the same matter before it is broken, then only one expiation is required of you, unless the oath was made under the influence of waswas unintentionally, in which case nothing is required of you.