In the law of impediments, preventing a ruling from arising differs from preventing an established ruling from continuing. Some impediments block initial formation; others affect an operative status later.
The creation of a contract and the continued existence of a related right are different stages. One cannot assume the same impediment affects both identically. Likewise, reaching a zakat threshold initially and maintaining relevant conditions over the required period involve temporally distinct inquiries.
Legal map: Identify when the ruling begins, when the proposed impediment operates, and which component of the legal effect it blocks.