A trend is a trend is a trend,
But the questoin is, will it bend?
Will it alter its course
Through some unforeseen force
And come to a premature end?

Statisticians believe that they can predict the "bend." I say that experts in the
content domain have a better chance of predicting when the trend will bend.

In particular, an article of interest:
A Simple Method for Assessing Linear Trend and Seasonality Components in Database Models.

In general, for articles of  the craft and scholarly elements of the profession of  Statistical Modeling and Analysis for Database Marketing click here.