It works like this.. you got ribbons and medals.. the ribbon bar (or fruit salad) is what you typically wear. Be it for duty, going to MOST ceremonies or doing things like 'manning the rails' as you enter/leave port or depart for deployment (Yes, I had one CO that made us wear our 'Class A' dress uniforms flying to/from our det sites. BLEH.. cause nothing is more fun that wearing the Navy Dress Blues all the way to Sciliy)
The medals/ribbons combo is use for certain events (Military funerals come to mind), as well as being designated for other events. I've had to wear the damn mixture for squadron retirements, relocation, military retirements, and a few other events that the coordinators called for them. I personally had a relatively mix with something like 12 medals out of my salad. The reason I say 'damned' because they are a. Expensive to mount when you have more than 4..(because if you have more than 4..they have to GODDAMNED OVERLAP.. so you have to PAY someone to do the damn things). b. The fuckers are DELICATE to the extreme.. I have ruined four sets going through hatchways and bumping to someone.
Most expensive set I ever saw was of a Senior Chief who was a former member of the Teams.. it cost him something like $350 a set. And due to being a senior NCO..had had a second set for his 'jacket' dress uniform as well. And he had some expensive ones.. like the Kuwait liberation medal. (the original GOLD ones)