Silverware is used from the outside in, that is, the pieces FARTHEST from the plate are used first, and so on. So if salad is served first, the salad fork is on the far left.
The soups spoon can come with the soup, or can be above the plate -- on the table, on the opposite side of the plate from the diner.
There is always fresh silverware with desert. It should come on the same plate as the desert.
No one should have to "lick" a fork or spoon clean to use with the next course. If you are removing plates, you should be removing silverware along with the plates. If you planned your table setting well (and no one lost or held back any pieces), your guests should have NO pieces left on the table by desert time.
Five of any one kind of utinsil (5 forks, 5 spoons, 5 knives) is the limit, but nothing wrong with less than 5. Too much silver makes your table look cluttered.
Have some spare pieces handy for folks who drop forks and have other outnesses. Even at formal state dinners, a head of state or ambassador can end up with no fish fork.
No matter HOW exaulted your guests, be sure to watch and count the silver carefully. You never know.