There are several factors that affect the price or value of a cover and they are not always related to the condition but obviously the better the condition of the cover the more likely it will achieve a higher value.
- the position of the stamps i.e. are they aligned neatly on the cover, not squint, or if there are more than one stamp that they are equally spaced and in a neat line
- the neatness of the address - for more modern covers it is generally better if it is typed but for older covers a neat handwritten address adds to the collectability of the cover
- the quality and clarity of the postmark - the clearer the postmark the better - too feint and it is harder to discern the date on it and if it is too heavy the postmark can look like a big black splodge. In addition the type and location of the postmark can add value to the cover particularly if it has some relevance to the issue itself
- and finally, this is most relevant when bidding for covers in an auction - demand. Correctly this should be supply and demand in that if there are few covers in existence or that rarely are offered for sale then this will lead to an increase in the price of the cover collectors are willing to pay. However, be aware that there may be occasions where a cover is not particularly rare or collectable but someone else who wishes to add a cover to their collection is up against you. If two people or more want a particular cover then this can drive up the price of a cover.