I remember having made a simple site for a small business I worked for. Told them to remember paying the annual 18$ bill for their domain name. Cue two years later and they forgot, the domain was taken by some squatters. They were asking for 1000$ annually for the domain name !

I told them not to pay and of course the name was available a year later at the same original price of 18$ a year. They never forgot after.