A short answer: I dunno.
The longer answer: It depends on many factors, including the mineral content of the water in your area, whether or not your water is soft or hard, the brand that you’re using, etc…
The reason that they recommend HE detergent is that there is so much less water used, so they want to be sure you don’t use too much regular soap and not have it all get rinsed out. I have HE machines and have used them with regular detergent from 2004 until 2006. In 2006 I started using homemade laundry soap.
Occasionally my clothes will start to develop a film and my whites get a little dingy. When that happens, I add some other things to the wash for a couple of weeks and I get back to normal. The things that I add are 1/2 cup of Borax per load and a medium load sized measure of color safe bleach. Before I tried the Borax, I used to use OxyClean. Borax just seems to be cheaper and does just as good a job. Don’t tell Billy Mays, or the folks over at the sham-wow thread. :blushing:
My machine has held up well. If you’re concerned, use the HE stuff. If you’re willing to take the risk with your machine and your clothes, go the cheaper route. I guess I wasn’t too worried because I bought the 5 year warrantee on the washer and dryer. I don’t normally do that, but this was back in 2004 when the HE machines first came out and the washer was almost $1000.