JPEG compression is a very efficient image compression algorithm designed specifically for saving photographic images. It takes advantage of how we see color versus brightness to only save information needed to reproduce the image for people to view. Image data is lost during compression but at high levels of quality you will not see a difference between a level 10 JPEG and a Tiff printed to paper. JPEG compression is perfect for transient files for sending to the lab for printing but avoid using the compression as a working file type. Also avoid opening a JPEG, making changes, and resaving it again as a JPEG repeatedly. If your workflow calls for this to happen, save your files as Tiff or PSD files until they are complete and ready for output. At which time you should save them as level 10 JPEG. Any JPEG artifacts you see in your prints come from the JPEG file coming out of your camera, not from saving them as a level 10 for output purposes.