Answered by Shaykh Sohail Hanif, SunniPath Academy Teacher
Is it mandatory to wipe the feet every time I make wudu, or is it OK to just clean them once in the morning, and clean the hands, mouth, etc. on every other time during the day?
If one means ‘wash’ in place of ‘wipe’ then yes it is incumbent to wash one’s feet for each ablution. It is not a condition that it be washed after one washes the rest of the limbs that get washed in the ritual ablution; if one washes one’s feet before the face the ablution is still valid.
In place of washing one’s feet one is able to wipe over one’s footwear if it suits the conditions stipulated for footwear that one is able to wipe over. Of the most important of these conditions is that the footwear be thick enough that one can not see the skin through it and such that if one wipes over one’s foot one does not feel the wetness seep through to the foot as one wipes and that the footwear is tough enough that one can walk a reasonable distance without them ripping the size of three small toes. In such a case one may wipe over the top of one’s footwear provided that one was wearing them before one’s ablution was nullified. One may continue to wipe over them for twenty four hours after one’s ablution was nullified after which one must remove them and wash one’s feet. (al-Hadiyya al-‘Ala’iyya)