In the Sierra Nevada, you can generally count on one of two situations: in the heavily used areas where the bears are habituated to humans and eagerly looking out for human food, those bears will check out your campsite regardless of whether they can smell food or not. They smell people, and they know people have food. But they are not interested in you - just your food. So unles your tent smells pretty strongly of food, it will smell much more strongly of you - at least mine will! And the bear will keep looking for the food.
The other situation is when you are well away for the trail and you encounter a wild bear, not used to people. those bears will usually avoid you like the plague. I would guess that if you were to leave your foodbag on the ground well away from your tent, they might go after it, but otherwise I wouldn't worry about a residue of food odor on your shelter if you've cooked under it on that rare occasion.So while cooking in the tent is not a great idea, I do it when I have to - which is rare in the sierra, since I can usually find a big tree to cook under if the thunderstorm comes at dinnertime, or just wait until it's over. If I was to spill some food inside, then I would be diligent about cleaning it up as thoroughly as I could.
Personally, I use my canister almost all the time now in the Sierra, even in non-problem bear areas. I have a couple of main reasons: one, it keeps the other, smaller critters out - to whom I have lost much more food over the years than to bears. For another, I consider it prevention. If an arae that hasn't had bear problems gets more usage, and people are careless about their food storage, then the bears may become used to getting human food and become a problem. Prevention is much easier than correction. And in areas where canisters are not required, but bears might be an issue, I am done with hanging my food. I've done it too many times, I'm sick of choosing campsites based on the trees instead of the view, I'm just done.
So store your food properly, and make a reasonable effort to keep the food odors off your clothing and shelter, but don't worry about it too much. And yes, It makes a HUGE difference to avoid bear hangouts. If you camp off the trail, away from the usual spots, you're very unlikely ever to see a bear or have any bear problems.