Actually Janet is being the sensible one here.
Dishcloths harbour more bacteria than just about any other place in the house including the kitchen bin, unless you kill the bacteria by, boiling, and/or drying them out between uses. Rinsing them out in warm and possibly dirty water, and leaving them damp creates the ideal environment for breading bacteria, and spreads it from one wash to the next.
By all means re-use cloths, no need to throw money away, and there is also no need to become paranoid about cleanliness and bacteria, we only live because of the stuff, and it only gets to become a problem in really bad conditions (Killing off good bacteria can also be a problem, as it lets the bad stuff take over).
The best plan is to have two or three cloths on the go, one in use, one drying off and one clean and ready to take over from the first.
Bob