It would be great if all stamp dealers only had stamps in the grade of superb and we’d never have to worry about centering and condition and the varied prices that come with each designation.
I believe that dealers should not list anything beneath a certain condition unless it has a strong interest factor that overrides whatever fault (tear, wrinkles, stain, etc.) that might keep a lesser item from being listed. Some of those considerations include a cover with highly unusual markings, stamps seldom seen, a noted pedigree or provenance, etc.
But we do have good descriptive terms to denote centering of our stamps. And the collector must remember that centering is a major part of condition. And condition is to collectibles as location is to real estate: the primary concern. Without acceptable condition the value of your stamps becomes less until in the poorest condition your stamp’s condition hits bottom where it is known as a space-filler, the pariah of stamps, only good to put into your album until the time you can acquire a more acceptable copy.
Tip: Remember when you buy to buy the best condition you can afford. You will thank yourself when you sell your collection at some point in the future.
There are different opinions of what designations should be used to describe centering, but what follows are the most basic, well understood by the knowledgeable collector. One can have long debates on shades of difference between conditions: “Is it F++ or is it VF- ?” But the basic grades of a mint stamp, based on centering are:
S - Superb: As close to perfectly centered as possible. Collector will pay a premium to catalog value.
XF - Extremely Fine: Almost perfect centering. Collector may pay full catalog value for such a stamp.
VF - Very Fine: Design well away from perfs. Centering not perfect, but more than acceptable. Collector may pay a bit of a premium to average retail prices. The most common stamp grade of stamps found in most collections.
F-VF - Fine to Very Fine: Design fairly well away from the perfs.
F - Fine: Perfs very close to the design, not touching.
G - Good: Perfs touching the design.
Avg - Average: Perfs cut into design.
As far as slabbing stamps; that is, the practice of grading services that encase stamps in plastic for eternity, with high grades to deserving stamps, allowing sellers to net high sums for a stamp that otherwise might sell for a bit over catalog value if not professionally graded: My feeling somewhat matches Joni Mitchell’s lyric in her song about progress, Big Yellow Taxi: “They took all the trees, put em in a tree museum/ And they charged all the people a dollar and a half just to see em.” I may not be an official tree hugger, but I like my trees and stamps out in the open, where I can see and touch them, not behind a pay-wall of plastic.