The designs of some stamps extend beyond the perforations or die cuts.
For example, take Scott #1489-98, the Postal People issue. The strip of ten stamps shows various postal workers. Notice that some of the stamp design of the rightmost and leftmost stamp extends a few millimeters into the margin. I can think of other issues where the stamp design extends beyond the bounds of the stamp itself.
This raises the question. If, in this example, you have a strip of ten of the Postal People issue, is it necessary to have the margins too so that you have 100% of the stamp design? The answer is no.
Some collectors may prefer to have the margins to show the additional design work. Thatís their preference. There is nothing wrong with that. There is no price difference though between a strip of ten without a margin and a strip of ten with a margin. Most collectors are interested in what comes between the perforations and die cuts. Anything outside is superfluous.
There are some instances where the stamp design takes over a large part of the margin area. Take the Legends of Hollywood panes for example. The margins contain significant design elements. Collectors will save these as full panes to capture all of the design work. Full panes like these are noted in the Scott catalogs.