I manage a commercial/industrial HVAC/R supply house. I've been waiting on some parts for over a year. It's been good and bad and by that, I mean I've been able to upsell, sell in bulk, and get PO's quicker. Fortunately, for me, I'm not an OEM. The OEM's are suffering because they can only sell their stuff. For example, the local Carrier distributor sells Carrier gas valves, which are manufactured by White Rodgers. They need to purchase them from Carrier whereas I buy directly from White Rodgers. Carrier ran out of certain gas valves this winter. I have since run out of the White Rodgers valves because people couldn't get them from Carrier. The other advantage I have is I can cross reference many out of stock parts to another brand. The OEM's can't do this. Lastly, I'm smart enough to sell a single stage gas valve as a replacement for the 2 stage valves they(we) are out of. A 2 stage gas valve has a low fire and high fire vs a single stage gas valve that only fires on high fire. Yes, you'll lose efficiency but you'll have heat. The OEM will only sell you what belongs in thee furnace. This summer should be interesting as there is a shortage of compressor components. No components means no compressors and yes, I've been waiting on some compressors for over a year. Again, I have the ability to cross reference to other manufacturers.