What you are doing is essentially taking all time off and putting it into one pool. The positive is that it is far easier to administer, provides maximum flexibility to your employees, and eliminates the challenges faced when time off taken doesn’t perfectly fit into holiday/vacation/sick (e.g. child is sick, snow day). The down side is that all sick time goes from time to be taken only for illness to possibly being taken as vacation. Overall, more time off may be taken, resulting in less productive hours for your company per year. Also — you have to watch the employee who exhausts their PTO too early in the year, leaving them with no time to be available in case they’re sick.