PTO is an all-inclusive time-off package that gives employees a set number of days a year they can use for vacation, sick time, personal time or other needs. Employees don't have to explain how they use the time. PTO is a growing trend: A survey by Mercer found that 63 percent of employers polled were using PTO in 2015, up 38 percent from 2010.Most companies don't allow PTO to roll over into the next year. However, some states â such as California, Nebraska and Montana â have laws that prohibit âuse it or lose it" policies, so be sure to understand your state laws. A survey by the Society for Human Resource Management (SHRM) found that most employers based the number of PTO days available on the length of employment (on a sliding scale) and gave employees 13 to 26 days per year.