The ability to grow without copying is already part of how slices work. Every slice is really a 3-word tuple of pointer, length, and capacity. If not explicitly set with make, the capacity property defaults to a value that fills out the size class of the allocation. It just so happens that, in this case, the size of the Task type doesn't allow for more than 1 value to fit in the smallest allocation. If you were to do this with a []byte or []int32 etc., you would see that the capacity doesn't necessarily start at 1: https://go.dev/play/p/G5cifdChGIZ