Yes, that seems like a good solution that anyone could figure out in about 5 minutes. So why do companies go with "unlimited" vacation instead? Because its just a money saving scam. If the company doesn't specify an exact amount of vacation then they don't have to carry it as a liability on their books. Hence the name "unlimited" which really just means "unspecified". Startups especially like it because accrued vacation money must be set aside leaving leaving less runway. It completely screws the employee because vacation was actually money that had to be paid out if they left. So the employee is out that money, usually at a time they need it most. Getting fired with 8 weeks vacation banked it not nearly as risky as 0 weeks.