The hidden cause most builders miss
The most critical part of your retaining wall is the part you will never see: the backfill and drainage system.
Without heavy-duty agricultural pipe wrapped in geofabric, and backfilled with clean drainage aggregate, water becomes trapped.
This trapped hydrostatic pressure will eventually push the wall over—no matter how thick the concrete sleepers or timber posts are. It is the #1 reason we are called in to replace failing walls.