I have found the name brand precuts to be pretty accurate in measurements. But ones that have been cut by stores to sell as precuts tend to be off. I pretty much stick with the Modas, and others . I love Jenny Doan's tutes for speedy assembly of quilt tops. I have file cabinet drawers that are filled with layer cakes- 3, at least 4 drawers of jelly rolls, some are solids in one drawer, one drawer of batiks, and at least one more drawer with prints, and then another of charm squares. Then I have a file drawer filled with precuts I have cut from my scraps. Last year I made 43 quilts, most were lap size for charity gifting. This year my goal is just to use stash stash and more stash.