I can read USAF and the DoD ones. Some Navy and Army ones escape me as I'm not that familiar with the specific service medals and ribbons (ribbons signify medals and for specific accomplishments, like expert marksman as noted, or for a short ((1 yr)) or long ((2 or more yrs) overseas that aren't medals.)
Enlisted who later commission can wear medals/ribbons earned in that status as those are for all the individual's accomplishments and/or service. Same as those who switch from one service to another.
I believe most US personnel with any experience glaze over the medals/ribbons as many are "I was there" and we all know it.
Seeing a DFC or higher, or a 'V' on a medal that has that designator is an entirely different matter.