In this video, several of my friends and I propose ways to cut a 75-minute Excel process down to under 15 seconds. As expected Diarmuid Early posts the fastest time with an under-10-second solution. But Diarmuid warns about a possible problem in the data, which makes a method proposed by Peter_SSs and Anup Agarwall the fastest and safest method.

The formula methods from others:
https://www.mrexcel.com/board/threads/excel-insert-blank-row-after-every-two-data-rows-shorts.1217116/
https://www.mrexcel.com/board/threads/insertblankat.1217374/

Table of Contents
(0:00) Hurricane Ian delay
(0:34) 2-minute solution for OP
(1:11) 53-Second solution
(1:30) Too Slow
(2:10) Fastest Excellers
(2:30) Anup Agarwal
(3:07) Diarmuid Early I
(4:06) Diarmuid Early II
(4:35) Imagining OP data
(4:52) Other solutions
(5:09) Formula dependencies between rows
(5:20) Anup / Peter solution
(6:22) Thanks to Everyone