I sometimes reuse the used plates in my room.
Why would you reuse the plates?
I do that because I am poor.
It is good to re use items if you can to save the environment. It might be proper to rinse or wash them off so you don't contaminate food first.
So if I go and tell someone that I am poor, that excuses my behavior?
No of course not, I'm just saying that if you are sanitary about it  then reusing plates is perfectly fine.