The federal position, stated carefully because the usual version is too strong. The Fair Labor Standards Act sets a minimum wage, an overtime requirement, recordkeeping obligations and child labor rules. It does not require payment for time not worked, and the Department of Labor's own regulation says so in the plainest possible terms. Discussing an example of vacation pay, 29 CFR 778.219(a)(1) adds a parenthesis: "Nothing in this example is intended to imply that the employee has a statutory right to $576 or any other sum as vacation pay. This is a matter of private contract between the parties who may agree that vacation pay will be measured by straight-time earnings for any agreed number of hours or days, or by total normal or expected take-home pay for the period, or that no vacation pay at all will be paid."
What is too strong is the claim that no federal law requires paid vacation. Under the McNamara-O'Hara Service Contract Act and the Davis-Bacon and Related Acts, vacation and holiday fringe benefits are required for covered workers on certain federal contracts where the applicable wage determination says so. 29 CFR 4.173 states that "most vacation fringe benefit determinations issued under the Act require an employer to furnish to employees working on the contract a specified amount of paid vacation upon completion of a specified length of service with a contractor or successor." So the accurate statement is about the FLSA specifically, and a worker on a covered service or construction contract is a genuine exception rather than a technicality.
Four design choices, and they matter more than the headline number.
Accrual or lump grant. Time that accrues per pay period exists only once earned, so a new employee's balance is small and a departing employee's is prorated. Time granted as a lump sum at the start of a year exists immediately, which is better for the employee mid-year and raises the question of what happens if they leave in March having used it.
Cap, rollover, or use-it-or-lose-it. A policy may let a balance carry forward indefinitely, carry forward up to a cap, or expire at year end. This choice determines whether unused time is a stored asset or a perishable one, and it is the one that most often produces an unwelcome discovery in December.
Payout on separation. Whether accrued and unused time is paid when employment ends depends on state law and on the employer's policy, and the answer varies. It is worth establishing before resigning rather than after, because in some arrangements the balance is worth real money on the way out and in others it is worth nothing.
Whether other leave can consume it. This is the least-known and the most consequential. Under 29 USC 2612(d)(2)(A), "an eligible employee may elect, or an employer may require the employee, to substitute any of the accrued paid vacation leave, personal leave, or family leave of the employee" for family and medical leave. Paragraph (d)(2)(B) extends the same power to accrued sick or medical leave where the leave is for a serious health condition. The employer's power to require substitution is what makes the two entitlements non-additive: someone budgeting twelve weeks of job-protected leave plus a holiday later in the year may find the holiday has been absorbed. That statute also confirms the underlying position, since 29 USC 2612(c) provides that the job-protected leave itself "may consist of unpaid leave."
Two mechanical consequences of a payout that are easy to get wrong. Payment for time not worked, and payment for leave you gave up, are not compensation for work. 29 CFR 778.219(a) treats pay for forgone leave as excludable from the regular rate and states that "since it is not compensation for work, pay for unused leave may not be credited toward overtime compensation due under the Act." The practical readings are that a PTO payout does not increase the overtime rate, and that an employer cannot use it to offset overtime it owes.
What a balance is worth to you depends on how you are paid, and the two answers genuinely differ: for a salaried employee more paid leave does not produce an extra payment but raises what the same annual salary buys per hour actually worked, while for an hourly worker paid leave is additional paid hours and behaves much more like cash. Total compensation carries that distinction in full.
Unlimited PTO, described accurately. A policy with no stated allowance removes an accrued balance, and with it removes anything to cap, roll over or pay out on separation. Whether that is favorable depends entirely on whether the culture supports taking time and on what state law would otherwise have required at separation, and both of those are questions about the specific employer rather than about the policy design.