I have an unopened tub of waitrose cheese sauce that I was going to make a tuna veggie pasta thing for my DD and then freeze down the extra. The thing is that it's use by date is tomorrow 7th and I really can't face making it now, so it would all be made on the final day of it's shelf life.
To defrost I would usually pull it out the night before and then heat well the next day as we don't have a microwave.