Thanks a lot for the explanations!
These are scanned images. and some times, I want to destructively crop and rotate them so they can be viewed in simple image viewers quickly.
What I don't want is for there to be a loss of details, change in color, and so forth when I save them as tiff repeatedly. Of course, at this stage, I will not consciously adjust the color like you mentioned in Lightroom. However, I am worried that the simple act of resaving causes image quality degradation.
Just to conform, what's I'm doing won't degrade the image in the ways I'm concerned?