Paid leaves are generally a pre-determined number of paid leaves an employer offers to employees, every year. This leave is treated more like a benefit from the employee's point of view. Employees generally give a lot of importance to the paid leave policies and its flexibility offered by the employer, when choosing to work at their organization. 

The most common different types of Paid Leaves are as follows:

Casual/Sick Leaves: 
This type of leave is generally given to employees for a short/quick period away from work, mostly for personal reasons or sudden sickness/ill health which wouldn't last for more than a couple of days. Most companies give around 6 Sick leaves and about 10-12 Casual leaves every year. Any unused balance in these leaves generally lapses at the end of the annual leave calendar.

Vacation/Earned/Annual Leaves: 
Most countries have made statutory provisions to count a certain number of days every year as "paid annual leave", for a period longer than 8-10 days at a stretch. These leaves are generally expected to give the employee a longer time-off duration from work. The general average observed around the world is of about 12 Annual leaves every year. The employees can use this time for family vacations, cooling off from a year full of hard work, or any other reason. Any unused balance of these leaves are generally carried forward in full/less to the next years' Annual leave balance.

Paid Time Off (PTO): 
In recent years, many companies have started adopting the PTO system of leaves. These companies choose to avoid complications of dividing leaves into different types like Sick, Casual, Vacation, etc. Instead, they collect all the leaves (total annual eligible figure) into a pool of leaves, like a leave bank, for each employee. This pool of leaves is called Paid Time Off or Personal Time Off (PTO). Employees can then use their PTO as and when they require, but generally employers expect a minimum advance notice about it. In most cases where PTO is used, it covers the vacation, sick, casual or any other type of possible leaves.