I make sushi rice primarily for onigiri, which I make for my lunches. When I make onigiri I usually make enough for 3 or 4 days at a time, wrap them individually in cellophane and keep them in the refrigerator. Because I store them this way, I can't wrap them in nori or mix the rice vinegar directly into the rice. The nori gets all soft and nasty and the rice vinegar just becomes too potent when it's wrapped in plastic for days on end. So, when I take out onigiri for my lunch, I unwrap it from the plastic, apply my rice vinegar with a spray bottle, add my nori, and sprinkle on sushi spice mix. Then I re-wrap the onigiri and put it in my lunch bag.
See Also
Sushi Rice | The Modern Proper