I wash and reuse all plastic ware whether it's forks/spoons/knives or plates or containers. The only thing I don't use it for is heating things in the microwave. I can't bear filling the landfill with things that are still usable.
I only wash full loads of clothes and dishes. I tend to have a conservative mindset but also live in an area where water is expensive and we have rationing as far as watering lawns etc. It's not as bad as California but still have to be very careful. No one would know if I ran a partial load of dishes or clothes but I'd feel guilty so I don't do it.