Harrison’s recommends all birds start out and remain on High Potency for a period of no less than 6-8 months.
Subsequent to this period, Adult Lifetime is an optional formula for some species. Most birds can remain on High Potency.
(Some birds, including African Grey, macaws, larger Cockatoos etc should remain on High Potency for life).
Only in situations directed by your avian veterinarian would Adult Lifetime be directed instead of High Potency.