A salaried employee's hours are not counted, but the days they work are--or rather, if they work less than the usual workweek, the shortfall is counted. The normal workweek is based on 5 days. If you work 5 or more days per week, it doesn't matter if you work 2 hours or 12 each day: you get your normal weekly salary, no more and no less. But if you work less than 5 days, for each day less you work, you lose one day's worth (i.e. 1/5th your weekly) salary), even if you work in excess of 40 hours total during the remaining days. That's why salaried employees need paid time off (like sick or vacation days) when they take days off from work, since taking or missing a whole day reduces pay unless you have PTO.