Hey @Pcgiguide , Great question and one I am interested to hear form others on!
I have used Tech Wash in the past before I switched to Edelwiess Rope Wash this past year. I have never used a machine to wash the ropes just my hand in a tub with some elbow grease. I feel like I see more dirt come out with the Edelwiess Rope Wash, but I might have just been getting my ropes dirtier that particular season. As to the frequency, I dont have a set schedule or count of climbs, if I find that my hands are a bit dirty (almost a black soot / film) from packing my rope up I make a mental note to clean them. But I dont climb as much as I would like so lately its been every other season. It should be noted I only have dry core / dry sheath ropes in my rack and my experience in cleaning them is limited to that style rope.
I hope this helps. Please report back to how the Sterling Wash works for you!!