聽了某分享，聽到 :wq 和 ZZ 一樣都是儲存並關閉，和印象中的有些出入，所以直接 :h 查 vim 的說明。
:h wq
Write the current file and close the window. If this was the last edit-window Vim quits.
Writing fails when the file is read-only or the buffer does not have a name. Quitting fails when the last file in the argument list has not been edited.
:h ZZ
Write current file, if modified, and close the current window (same as “:x”). If there are several windows for the current file, only the current window is closed.
所以主要差異有：
:wq不管檔案是否有變更、異動，都會在 vim 關閉之前寫入檔案；如果使用ZZ則僅在檔案內容有變更時才會寫檔，否則直接退出 vim。:wq後面可以加上參數。例如寫入後關閉，但是希望另存新檔時，可以使用:wq new-file來要求 vim 將內容寫入其他檔案。