Many bands/artists release EPs and LPs.
I have noticed that many artists that are still on the beginning of their career release EPs.
What does EP and LP mean?
EP refers to Extended play. It is something between a single and a full CD (or LP); a little too short to be a full CD and a little too long to be a single.It usually has 3-5 tracks .
LP refers Long Play; it is a vinyl record. Per Wikipedia:
The LP (Long Play), or 33 1⁄3 rpm microgroove vinyl record, is a format for phonograph (gramophone) records, an analog sound storage medium. Introduced by Columbia Records in 1948, it was soon adopted as a new standard by the entire record industry. Apart from relatively minor refinements and the important later addition of stereophonic sound capability, it has remained the standard format for vinyl albums.
Size-wise (vinyl) : a typical LP would be 12" diameter, a single 7" and an EP 8-10" (measurements from my own collection). But over time, there have been variations in the sizes of LPs and EPs as the various wikipedia articles will tell you, so "typical" is an era-dependent term here.
Punk-era EPs often went in for experimental shapes and colours, and because EP is, of the 3 formats, the slightly non-standard one, there are (subjective) associations of "experimental" about the format.
An [EP] I always thought was a compilation of songs or variation of the songs similar to the (LP) it is trying to promote.
For example: Iron Maiden's Album/LP - The Number of the Beast released in 1982. In 1990 an [EP] is released called →Run To The Hills - The Number of the Beast← If sales of [EP] meet a certain amount it shows people are still interested in the songs (this is why they pick the higher charted 4 to 6 songs).
If sales are good as they were for the above mentioned [EP] You can rest, assured that a Remastered or Reissue or Deluxe Edition will be released. As it was in 1998 for Iron Maiden. In this bands case they released an [EP] for each one of their Studio Albums/(LP`s) in 1990 and ended up Remastering every single original Studio Album.