completely agree. The customer I am at makes use of Quest's Capacity Manager, so we get a GUI on top of that data, but a homegrown version can be as good (or better, as it can be built into any alerting system, whereas Cap Man is outside the alerting structure we have here - we can't see a referenece to "alert sent" for example).

Whether using Cap Man, or a similar tool, or a home grown tool - the importance of predicting, and then measuring, data growth is often under-estimated.