I've had to wash clothes twice for the following reasons:
1. Too much soap.
2. Too little water (operator error).
3. Stain on clothes, usually a type of grease.
The question is likely whether you have to wash clothes twice in a front load washer. Having never used one, can't say. I do know they can stink - literally. Less water translates to issues such as foul smelling gunk in the pipes connecting to the tub.
Have run into problems with water reducers on shower heads. That's a very real issue. Have also run into problems with the toilets now mandated by law in the US. The problem is insufficient flow. For whatever reason, have also had difficulty adjusting replacement flaps, which makes no sense at all: the same type of flap is used on old and new commodes. The only reduced capacity toilet I've seen that worked properly was a pressure assisted toilet. They are more expensive and I've never had to repair one, so I don't know about the expense of parts or difficulty.
So here's a problem: I can't tell if pressure reducers translate into more water usage. I suspect it ends up saving nothing due to longer shower times. I do know that multiple flushes are an issue with modern toilets other than pressure assisted. Maximum tank capacity of new commodes in the US are 1.6 gallons / 6 liters while tanks between 1982 and 1993 could use no more than 3.5 gallons / 13.25 liters (yes, I looked it up). Tanks older than 1982 held 5 to 7 gallons (18.9 to 26.5 liters). I've never encountered a 7 gallon tank, so let's say 5 gallons / 18.9 liters was the norm. Two flushes with a 3.5 gallon toilet used more water than one flush of a 5 gallon toilet. Four flushes with a 1.6 gallon tank exceeds 1 flush of a 5 gallon toilet. Yes, I've seen it, and good luck with four. Blame it on old plumbing or whatever, but it does happen.