Perfect. In that case, consider something along the lines of this for your accrual - lick to enlarge;
My customers all adhere to UK traditions, which sees them run holiday/vacation on an annual basis from Jan 1st to Dec 31st, which awards them their entire leave balance upfront on the first day of the calendar year. Employees with long service get their extra day on the first instance of January 1st after they meet the threshold. Ergo, someone who reaches 24 months of service on July 1st 2022 will only get that extra day available on January 1st 2023 as part of their 2023 leave balance.
That's standard - at least, it is over here. Such plans also use 'Plan start date' as the accrual basis with a start date of Jan 1st. The 'Accrual type' (screenshotted above) is the config element you use to then decide what the right accrual amount should be.
Something more unconventional may be required if you want the day to become available from the very moment the workers hit X months of service. At that point, I would encourage 'Employee-specific date' for the accrual basis, but it's not something I've ever seen with my customers for annual leave.
