The best way to explain technical debt is by analogy: Technical debt is what happens to your entertainment center when you buy a new Playstation. To do things properly, you should buy another HDMI cable, run the cable through your cabinet around to the TV, on a dedicated input.<p>But that's not how it happens. When you bought the Playstation you also got a copy of Call of Battlfield Honor Brothers, and your friends aren't going to wait half an hour while you do that. So you steal the AV cords from the Wii, run them in front of the DVD player, and plug them into the XBox's TV port.<p>So now, the system still works, but it's not ideal. You have to move some cords if you want to play a DVD. You have to unplug the Playstation if you want to play Minecraft on XBox. And heaven help you if you want to play Wii Bowling.<p>Now imagine this happens many times over several years. You get a new XBox. And a Bluray player. And a new sound system. Each time you do what it takes to get things working, and no more. Pretty soon, just to watch Netflix you have to rewire a whole switchboard of cables.<p>At some point, you need to pay off your technical debt. In this case, by taking a whole Saturday to unplug everything, buy some new cables, and re-route all the connections in a clean, logical way. It's the last thing you want to do while your friends are playing Band of Duty-bound Heroes IV, but if you don't, you'll be rewiring Ethernet cables in order to watch Hulu until the end of time.