The idea of roasting at home is completely new to me, do you roast a small amount? Is it an on demand thing where you need a couple cups of coffee so you roast

The idea of roasting at home is completely new to me, do you roast a small amount? Is it an on demand thing where you need a couple cups of coffee so you roast some beans or you do a big batch at once? Do you need special equipment to roast at home?