I don't seem able to cook just enough ever! I am always worried if I did that, that someone would want more.
However I am getting better when cooking for myself only as I used to cook enough for four and got so sick of eating the same things that I changed this!
I just follow a recipe in most cases, so however much the recipe makes, whether that's more or less than I what I need, is how much I get. I don't tend to have a required quantity though. If I make something, it is there for anyone. If they want it fine, if not, I'll have it, and it will just a little longer before it's all gone.
Depends on the kind of food I am preparing. When I make roti - Indian bread, Vietnamese rice rolls, Mexican quaesadillas etc then it is just enough for the number of us. When I make rice, curries etc usually there is enough left for another meal.
We try to make just enough, as it can be wasteful otherwise. It would mean we would eat it for lunch the next day. Sometimes it is hard to gauge exactly how many vegetables we need when they get all stir fried up, but we are mostly near to the mark !!
95% of the time we make more as we freeze the leftovers for extra meals when we can't be bothered cooking (read too hot to cook) and also freeze our spinach direct from the veggie patch along with soups so there is a good selection of food available at any time.
No. It's cooked for just under 5 minutes, drained well and cooled slightly then put into the food processor with salt and pepper until finely chopped then transferred to freezer containers. When we want to use it, thaw out, squeeze as much fluid out as you can and add a little sour cream and heat in microwave. If you didn't want to add sour cream you could also add to mashed potato as the Dutch do.
I try to freeze meat in portion sizes for one but sometimes I get two meals out of one piece if I am adding a lot of veges to it. I am not averse to eating leftovers at all but if I keep everything in "cook it and eat it" mode then my fridge is less cluttered. I hate a cluttered fridge. I do make an exception for curries because they are always nicer the second day.