In AEM, you can copy-paste components. You can do this one one page, but even across pages : from one page to another.
- Simply open two tabs with the pages that you want to edit
- copy the component or column-control by either clicking the button, of pressing ctrl-C.
- Open the other tab, make sure you select the correct element to paste in, and press the paste button or ctrl-V.
This can be handy build a page quickly without having to do it manually. If the page is 100% identical, you can always use the copy-flow in the AEM-treeview to copy the page.