sometimes I do it that way, but usually I do the blocks first and then cut the sashings--because I may change my mind about sashings, as some have mentioned, or it will look differently after the blocks are done. Since I'm working for stash, that works for me. if I had bought everything at the fabric store and kinda HAD to use what I had for each thing, I'd probably go ahead and cut the sashings at the beginning if I were sure I was going to use what fabric and already knew the size, etc.