Disco makes your money go further.

These disco tracks really need to be played from start to finish, despite all being around 8 minutes long. The length of the songs is a brilliant thing, however. There are two reasons why these songs, and many others of the 1970's, were so long.

1. In the 1970's people did not have last.fm, itunes or spotify (in the case of the latter, still no-one uses it). This meant the only way people could arrange playlists would be to use a live DJ, and even Isaac Hayes, at the height of his resplendent decadence and overspending, probably wouldn't have employed someone to mix next to the bed as he got his jig on. In the 1970's, people would have to shag to an album, or an 8minute single. A pre-coital selection of a three-minute punk song could have serious consequences for a man attempting to ensure his partner could expect at least something half-decent in the sack.

2. In the 1970's, someone predicted that the quality of albums would deterioriate and that people would like to buy singles individually from online resources. This oracle of music realised that people would want to get their money's worth for 79p, so would prefer long songs than slow songs.