Decision step 1: mark the failed zones
Draw the modem, work areas, TVs, bedrooms, outdoor edge, floors, and thick barriers. Start with a two-pack when the main unit plus one well-placed satellite can serve the important zones. A third node earns its place only when it serves a separate floor or wing, or creates a stronger intermediate path.
Decision step 2: test the upstream link
A wireless satellite must still hear a strong upstream node. Place it before the dead zone, then measure latency and throughput where it will sit. TP-Link explicitly notes that adding units does not always improve throughput or stability; a third weak link can add roaming and airtime complexity without repairing coverage.
Decision step 3: use Ethernet to place for clients
Ethernet backhaul lets a satellite sit where client coverage is needed instead of where a wireless relay remains strong. In router mode, keep the switch and satellites on the LAN side of the main Deco. Check the negotiated speed of every switch port and cable before paying for a faster mesh model.
Decision step 4: add the third node only after measurement
Install two units, update firmware, test the real rooms, and inspect the Deco app's node relationship before opening or buying a third. Add it when one important zone remains weak and the proposed location has either a strong wireless upstream path or Ethernet.
Choose BE63 versus BE67 after pack size
Node count fixes coverage geometry; the model choice fixes radio and port capacity. BE63 is the disciplined choice for four 2.5GbE ports per unit and a 2.5Gbps wired plan. Compare BE67 when a defined 10GbE path or higher wireless capacity has a job. Do not buy one fewer node merely to afford a faster model if the layout still needs coverage.
Match pack size, hardware, and region when comparing price
Retail listings can describe the BE63 as a 2-pack, 3-pack, 2-piece, 3-piece, or whole-home system. Normalize price to the same model, hardware version, region, power accessories, seller, and node count. Also compare a two-pack plus one compatible add-on because bundle pricing changes.