The Only Home Workout Equipment I Use

This might seem random, but it occurred to me recently that there is one piece of home workout equipment that I have used for well over a decade and I never plan on not using. It's extremely cheap (compared with a gym membership), doesn't take up space and it gives me the freedom to be able to work out at home without compromising on the effectiveness of the workout.  It even worked for me while I was at university, when I was basically living in a shoebox in London. (Come to think of it, I must have been using it for almost 2 decades).