sleep routines or random sleep

being unemployed due to disability,i have the option of sleeping whenever i wish.and i do,i tend to sleep in bits,by that i mean i dont sleep the average 8 or so hours straight through,i sleep a couple of hours here and there,in and out of bed at random times,sometimes up at night,i never sleep in ways that my body can get used to,any time within 24 hours i could be asleep.are rigid hours important,or is that something unimportant?also,does the brains sleep cycle reset itself after being awake for long enough,or,does it sort of continue where it left off,for example if you wake up during rem stay up all day,do you immediatley hit rem when you next sleep or is the sleep cycle reset?