Rob Farley cautions against rash decisions on three topics:
We’ve already mentioned how clustered indexes can help avoid some of the problems with heaps, but I’m rarely in favour of the standard clustered index key choice – that of an ever-increasing identity column. The arguments people make for this are typically around avoiding page-splits, and the smallness of the data type. But I see tables where the clustered index is on a unique ID column and nothing ever refers to it.
Read on for a dose of caution on three popular beliefs.