It’s easy to use thread count as a proxy for quality when buying sheets, especially if you don’t know anything about them. The trouble is that above a 400 thread count the number is essentially meaningless. Top-rated sheets had much lower thread counts than that. The problem is that it’s not possible to fit 1000 threads on a loom: sheets with a “1000” thread count can only say that because individual thinner threads plied into a strand of thread get counted.
Instead of looking for the sheets with the highest number, take time to actually read the package. The type of cotton is more important than the thread count. Combed cotton, Egyptian cotton, and Pima cotton are the best choices, and choose sateen or percale according to how soft or crisp you like your sheets to be. (Consumer Reports doesn’t endorse this statement, but polyester sheets are evil and should be banished to spend eternity as painter’s drop cloths.)
Overall, don’t trust how a sheet feels in the store: what you’re really feeling might be fabric enhancers that will wash right out once you put them through the wash once.
Higher thread count doesn’t guarantee better sheets [Consumer Reports]
How to fold a fitted sheet