Traditionally, the distinction between acute and chronic pain has relied upon an arbitrary interval of time from onset; the two most commonly used markers being 3 months and 6 months since the onset of pain, though some theorists and researchers have placed the transition from acute to chronic pain at 12 months.:93 Others apply acute to pain that lasts less than 30 days, chronic to pain of more than six months' duration, and subacute to pain that lasts from one to six months.