Is the reward for fasting equal, or does it vary according to the effort expended in it?

If hardship is inherent in an act of worship and the worship cannot be performed without it, then the reward and recompense increase with the increase in hardship, based on the Prophet's (peace and blessings be upon him) statement to 'Aisha: "Indeed, your reward will be according to the extent of your exertion and expenditure." Nevertheless, the principle "reward is according to hardship" is not always universally applicable. In some cases, a lesser act of worship may be preferred over a greater one, such as shortening prayers for a traveler and lightening the two rak'ahs of Fajr.