Is expiation (kaffarah) obligatory for abandoning prayer out of laziness? And is it obligatory to make up prayers missed due to laziness? And is one who abandons prayer out of laziness considered to have left the fold of Islam? And what are the sayings of the Imams and scholars regarding this?

You are required to make up for the prayers you slept through or missed due to laziness, according to the majority of jurists. This is the more cautious and absolving approach for one's conscience. As for missing prayers due to laziness, the correct opinion among jurists is that whoever prays sometimes and misses sometimes is not considered an apostate whose disbelief takes him out of the fold of Islam. Rather, apostasy applies to one who abandons prayer entirely.