What is the criterion for combining prayers while resident?

The questioner : May Allah reward you, O honorable Shaykh: The hadith attributed to 'Abdullah ibn 'Abbas (may Allah have mercy on him), in which he said: Question: What is the definition, what is the criterion, for defining the hardship intended in this hadith that allows the Muslim to take this dispensation, and an example of that?

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful.
This hadith was narrated by Muslim from Ibn 'Abbas (may Allah be pleased with him and his father) meaning: so that it does not cause them hardship. Therefore, whenever there is hardship—and by hardship is meant difficulty—it is permissible to combine prayers, whether while resident or traveling, due to illness, rain, severe cold wind, or the like. Even a pregnant woman, if it is difficult for her to pray each prayer at its time, may combine them. Likewise, a nursing woman, if it is difficult for her to pray each prayer at its time because her child urinates on her, or the like, she may combine them. In fact, the scholars said: even if a baker is baking and fears that the bread will burn, and he is compelled to delay the prayer, he may combine it with the one following it as a combination of delay, and there is no harm in that. So the criterion is difficulty, what? Whether in the body, or in wealth, or in the family, or the like. Even if something is lost from you and you go to look for it, and you fear that the time will become tight, combine the first prayer with the second. Or if you fear that you will travel a long distance, combine the second prayer with the first. So the door of combining is wide, and praise be to Allah. Yes, it is ease.