As much as you might want a hard-and-fast rule here, I'm sorry to say it doesn't exist. Unfortunately, I can't tell you to wash them after every three meals, or after every pasta dinner. The best advice I can give you is to check them out after each meal.
There are, however, a few questions to ask yourself that can help you make this all-important decision.
1. Were they strictly decorative?
A folded cloth napkin almost always looks better than paper. If you're using them solely as decoration and taking them off the table once people sit down, there's obviously no need to wash them.
2. Who came for dinner?
Was dinner for you and your beau? If yes, the standards are probably a bit more lax than if you were hosting his or her parents. A good rule of thumb, though? If someone wipes their mouth with it, it's straight in the wash! Let's not be germ-spreaders, okay?
3. How messy was the meal?
If you're eating BBQ ribs, chances are your napkins will be filthy. But if you're eating with forks and knives, you and your guests might not have even used your napkins. Sometimes people just put cloth napkins on their laps and forget about them! In this case, there's no need to throw them in the hamper.
4. What color are your napkins?
If they're a darker color and your meal was not too messy, you're probably fine not to wash them after a single use. Ditto if the napkins have a busy pattern.
5. Do the napkin smell or have stains?
In your effort to avoid laundry you could be letting oil stains or food odors linger. No one wants to use a permanently stained cloth napkin or one with a mystery odor from meals past. Spot-treat stains when you notice them and wash them as soon as possible.
In closing, use your best judgment. We totally support a shortcut (or skipping certain chores entirely!) whenever possible. Just err on the side of cleanliness. And there is one silver lining I'll leave you with: At least cloth napkins don't take up too much room in the machine — it's not like we're talking about bath towels.
How often do you wash your cloth napkins?