In some HR systems you’re basically lazy-provisioned PTO time as it’s taken, so your amount of accrued PTO Time is always reconciled at the same amount of PTO time taken, leaving the available balance at zero.
In other systems, you technically have zero days of PTO available, and when you use it your balance goes negative. Which gets zeroed out at the end of the year.
In both cases, your PTO balance is never greater than zero, so you never have any unused days that would be subject to pay out.
They don't.
https://hrdailyadvisor.blr.com/2017/05/24/permanent-vacation...
"For similar reasons, more employers are also experimenting with open or unlimited leave policies, which can offer the same benefit. The general idea of an open or unlimited vacation policy is that the employee doesn’t really accrue or earn a set amount of leave per pay period or year. Rather, leave is unlimited and may be subject to few, if any, restrictions beyond supervisor approval and a reasonable assurance that assigned duties, projects, clients, and other workload-related details are managed during the worker’s absence.
Here, because employees are not accruing a set number of wage-equivalent hours per pay period, no compensation interest vests. After all, you can’t very well pay out “unlimited” vacation at termination."
I read that as if you are in a role with no backup or reasonable cover for your duties you can never take vacation. As I often find myself in that position I'd shy away from "unlimited vacation" roles.
I've never seen a company the doesn't track time off regardless of their policy.