Saving an image as JPEG repeatedly will not loose quality in a single editing session. The image also needs to have been altered in some way and saved and closed before any loss occurs. Some/all? image editors have to recompress during Save As.Even that is up for discussion. I tried resaving the same file 30 times at maximum quality. I compared it in photoshop using the difference mode to compare layers. No difference
Try your own test- it is easy.
Much of what we know is wrong.
So potential damage can only happen when an image is closed, then re-opened, edited, and saved. It is also important to realise that the recompression algorithms only effects colour by discarding/combining some information first then luminosity. It does not change resolution i.e. pixel count. The effect may be very subtle over many cycles and dependent on image content may be difficult to observe