MQTT topic naming for fleet of sensors, conventions that scale

[jhon_iot]

Deploying 50+ sensor nodes for facilities client. Topic naming is going to matter for the next 5 years of dashboards and alerts.

Conventions I am evaluating:

• flat: sensors/temp_lobby (simple, brittle when scaling)
• hierarchical: site/building/floor/room/sensor (Homie style)
• asset-tagged: sensors/{uuid}/temperature (DB-friendly, opaque)

Settling on hierarchical. Site=cir01, building=hq, floor=2, room=lab. Topic: cir01/hq/2/lab/bme280/temp.

Wildcards work for "all temp in hq": cir01/hq/+/+/+/temp.

IoT veterans: what topic structure did you regret after 2 years of operation? Better patterns?