Many of the people who read this will be software developers and therefore likely drink lots and lots of coffee. One of the things that you are probably painfully aware of is that coffee usually only tastes good right after its brewed. The reason isn't actually that coffee starts fermenting or turning (though coffee does lose some taste being open to the air for long periods of time), but rather that most coffee makers brew the coffee into a carafe which then sits on a hotplate for hours on end. This hotplate is pretty much perpetually burning and concentrating the coffee making it taste worse and worse and worse until eventually the resulting sludge is poured down the drain.
The hotplate technique for coffee thermal preservation is a very poor design . Not only does it, as mentioned, make the coffee taste disgusting, but it's also perpetually radiating a large amount of heat into the environment. Instead of letting your coffee sit on a hotplate, after it has brewed transfer it to an airtight thermos. After I have done this I am amazed at how good the coffee tastes, even hours later, and how much it retains its heat due to the excellent thermodynamics of a modern thermos. The pure inefficiency and poor results [gross coffee] of thermal hotplates under carafes is absurd.
If you think that you don't have the discipline to transfer the coffee to a thermal carafe (i.e. large themos) then get a coffee maker that brews into an insulated carafe. Generally these won't be airtight and hence won't preserve the flavour or heat quite as good, but it's still a huge step up from the old style of coffee maker.
We've all heard it as kids, but many of us as adults don't follow it: Close the refrigerator door! Don't stand there gawking in. It wastes tremendous amounts of energy, and it can considerably heat up food at the front and in the door reducing the time that it will keep for. Again this is really obvious however it's amazing how we lose that thought while we aimlessly "look" in while we really are thinking about what we should order in. Just keep it in mind.
Similarily, and again this is a no brainer that we just need to keep in mind, when you are cooking in the oven only open it for the briefest periods of time possible. An oven can lose a tremendous amount of heat for every second that you sit with it open as you carefully baste your fishsticks.