Parkinson's Law of Data

'Data expands to fill the space available for storage.', i.e. 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, (per Moore's Law) memory density available for a constant price also tends to about double once every 18 months. Unfortunately, the laws of physics mean that the latter cannot continue indefinitely.