I always cook ahead. Instead of cooking meals every nite, I cook large pots of stew, vegeteble soup, ground beef, spaghetti, hamburger helper, chili, meat loaf, pork chops, pork stew, everything that you can make in large quantities, I make. then freeze the rest in freezer containers, after burping the air from the container. Then pop in microwave to thaw, and heat and eat. So much easier on nites you just can't take the time to cook a meal. I know a lady that used to brown ground hamburger and store in a large freezer bag. always burp all the air out before sealing to keep as much air out as possible. Then she could dump as much or little of the frozen ground beef,( it was drained of all water and fat so it was still loose, not frozen in clumps) and zip the bag and refreeze, but if it's thawed it should be cooked and eaten right away as Carolyn R said cook once reheat once then pitch, but the huge bag of beef if scrambled and loose when frozen doesn't have to be thawed to be portioned out. You can just pour out what you want and throw it back in the freezer. I just buy hamburger in bulk, pack approx one pound in each bag, flat in freezer bags (zip kind) and freeze laying it flat. I always squeeze the air out of the bag b4 zipping closed.
Also, instead of buying the containers at the stores that sometimes won't seal, or zip lock bags that bust out the bottoms, I save all plastic containers that food comes in such as margarine bowls, they make perfect freezer containers. Cottage cheese tubs, mozzerella zip bags I put a drop of dish washing liquid in them with hot water, zip and shake, rinse and turn upside down over the dish washing liquid bottle to dry, re use those to freeze things in. They are stronger and last longer than any zip lock that you buy in the boxes from the stores. Also, mozzerella (or other cheese) cheese bags are perfect to freeze ground meat in them, and if when empty, they are too greasy to wash, then refreeze the bag, use again for hamburger. As long as the bag has been used for meat, and not left out more than 10 or so minutes, I throw the empty bag in freezer and re use them to freeze the next batch of hamburger. Every thing that comes in a zippered bag, I reuse over and over again, and the margarine/cottage tubs, same way. Helps protect the environment, saves on buying trash bags, the cost of buying the freezer containers that don't always work any way.