Scimmia

Depends on which "No Rinse" sanitizer you're using. The most common are Iodophor, Star-San, and One-Step. One-Step isn't really a sanitizer, more of a cleaner with a little bit of sanitizing ability. Even then, since it's bicarbonate based, it won't last long, a few hours would be it. Iodophor will last a bit longer, but it does break down, a couple of days would be stretching it IMO. Star-San, as mentioned, will last a long time, especially if you use distilled water. It's significantly more expensive, but it's much more convenient than Iodophor since you can keep it around, and it won't stain your equipment. You also don't have to worry about tasting iodine in your beer. Really, we're talking about pennies per batch, so even significantly more expensive doesn't have much effect in the end.