3D printed mounts in mechanical rooms: good idea or headache?

I’ve started leaning on a small desktop printer for quick one-offs: sensor standoffs, BAS cable guides, oddball brackets the catalog never quite has. For field fixes, it beats waiting a week for a custom sheet metal tab. But I’ve also seen a few “clever” prints turn into soft noodles next to a hot AHU or crack from vibration.

PLA doesn’t belong anywhere near a supply fan motor. PETG survives better but still creeps under load. Nylon or CF-nylon has been solid, and I’ve had good luck with heat-set inserts and oversize holes for slotted adjustment. If it’s in a return plenum, I switch to metal or a listed enclosure. We still answer to UL 94, NFPA 90A, and the AHJ, and no one wants mystery plastic in an air stream. ASA has been decent outdoors where UV cooks ABS.

Curious what others are using for durable, code-friendly prints in mechanical spaces. Any favorite materials, coatings, or print settings that hold up to heat, humidity, and vibration? And how are you documenting these parts in the set so maintenance knows what they’re looking at?