Parkinson\'s Law of Data
prov. "Data expands to fill the space available for storage"; buying more memory encourages the use of more memory-intensive techniques. It has been observed since the mid-1980s that the memory usage of evolving systems tends to double roughly once every 18 months. Fortunately, memory density available for constant dollars also tends to about double once every 18 months (see Moore's Law
); unfortunately, the laws of physics guarantee that the latter cannot continue indefinitely.