What is thread count? Why does it matter?

"Thread count in sheets can range from 80 to 700, although most stores sell sheets that range from 180 to 320. In general, the higher the thread count, the softer the fabric feels, but that doesn't necessarily mean the sheets will last longer (and sheets with a higher thread count are usually more expensive). One linens department manager says thread counts above 380 are "kind of a farce." Manufacturers twist two threads in a way that lets them double the sheet's thread count.

Recently, many linens manufacturers have touted thread count as the best way to choose a sheet. But others point out that the quality of the fibers and finish are more important to the sheet's comfort and durability. In fact, sheets made of linen, flannel, or jersey (those trendy "T-shirt" sheets) have low thread counts due to the type of fabric. A high thread count would eliminate part of the appeal of these sheets." [Source]

Now I'm off to inspect the thread count of my current sheets...