A normal approach is flown at 3º. This means approximately 320 ft per NM travelled.
Normal in a larger aeroplane, but what if you have an engine failure? Whilst some pilots may fly a 3 degree approach, it is more common to fly a 5 degree approach in light aircraft, commencing at 1nm from touchdown at 500 ft. When I taught MOD flying scholarships, CFS mandated the 5 degree approach. Three degree approaches are probably first taught for the IMC rating.
Ron Campbell brought most of his ideas from the RAF circa 1950s, they have largely been the basis of GA ever since however; with no APs to set things in concrete, there has been a natural drift. Perhaps the largest factor in destroying the Standard Circuit concept has been Noise Abatement, with local circuit patterns that are more concerned with missing some Nimbie's house than flying a safe pattern.