We eat leftovers a lot, reheating it in the pan where it was cooked. I'll make a stir-fry with a sauce and eat it for two or three nights. But I'll do all the cooking and the first eating on one night, then just re-make the pasta or rice the next night, since pasta dries out quickly and so does rice.
My rule of thumb is that prepared food isn't very good after a week. It's probably safe to eat, just not palatable. We will generally eat stir-fry Monday, Tuesday, something else Wednesday, and finish it off on Thursday.
It's very common for us to eat fish and rice for dinner and then for lunch the next day or so.
Garlic and onions won't dry out in a day if you put them in the fridge in a plastic bag. They'll last for a few days.
I generally don't do the prep the night before unless it's a complicated dish. Anything with dry goods is fine to do the night before. Veggies start to dry out faster, so I don't prechop them. But I'm quick with a knife.
I was a Peace Corps volunteer in Africa without refrigeration, so here are some unusual tips just for fun: Tomato-based sauces are good on the stove top for about four days if you heat them to boiling twice a day. Broth-based soups (fish head soup, yum!) can go by the same rule. Boil it in the morning and at night and it's fine to eat, and still tasty, even if it's at room temperature all day. Not that you have to do that here, but hey, info is free. And I wouldn't do that with any soup that has dairy in it.
We are big on leftovers. It saves a TON of cooking time, since we tend to go out and do stuff during the day and come home late and tired with no time or energy to cook.
Another generic tip is to have a fall-back meal that takes 10 minutes or less to prepare that everyone likes. We have cold plate. It's sliced apples, sliced sharp cheddar cheese (one of the bricks you slice, like Dubliner or Cabot), sliced smoked sausage (summer sausage), and crackers. All the food groups, relatively healthy, everyone likes at least one thing, and it's on the table in about 5 minutes. Sometimes I add carrots and hummus, or grapes, but mostly not. The kids pick and choose, and we're all happy. And it's less than $2 per meal per person, more or less. Those cheddar cheese bricks are good in the fridge for at least a week, and the other stuff keeps for much longer, so it's easy to just have it around if you think it's going to be "one of those weeks." Cold plate has become our Sunday night standby.
Also, some things reheat well and others don't. In general, pieces of meat do not reheat well unless they are in stews of sorts. If you are going to reheat a side like succotash, the microwave is best. Rice and pasta should be cooked fresh, or you can made fried rice with day-old cooked rice. Stews and soups and sauces (spaghetti sauce included) reheat very well and are often better the next day. It depends on how you cook. If you have the J. of Cooking, read through it. It's a great resource for a lot of things.