Product review (2 stars): Mine didn't break at all
Mine kept working perfectly and the parts didn't break.

My advice is to do measure up a mix of boiling water and cold water, perhaps with a little bit of thermometers and math.

This machine was pretty good at getting the dirt out, but then you have to rinse the clothes somehow (to get the soap out, if nothing else) and I never found a good way. I tried the kitchen sink, but that felt gross. And it was hard to work with the cold water for long enough.

I eventually gave it away to a friend because I got tired of the clothes always coming out sopping wet.
Many people have combined it with an electric centrifuge, but to me that kind of defeats the purpose. I don't have room for another machine, nor do I have room for dripping wet clothes hanging around for more than 24 hours. The whole point of this was because I live compactly.

Before I got this, I had used other methods of handwashing, including using a bucket. The Wonderwash gives better results but does not save labor, given that the majority of the time will spent on be rinsing and wringing.

But bottom line is that I used it for months and it did not break.