The name "unsharp mask" confuses people.
It is actually the name of a darkroom technique to sharpen up soft photgraphic images.
It works well with some adjustment for each photo.
At one time the tiff format was standard for photos.
Tiff files had a problem with page layout programs that could not discern the difference between white and transparent backgrounds.
Jpeg file are the standard for photos now. However problems can occur because the format is "lossy".
Every time you open, edit and resave the file more data is lost in compression.
So when creating a jpeg keep compression at the level which creates the largest file size for print or further editing.
For web, you can go back and and save it as a smaller more compressed file for fast internet loading.
When working extensively on a photo, just keep it as a psd until your done.
When working on jpegs from phones, digital cameras and stock photos, remember to save an original backup copy.