The tardis is not a very helpful location in answering this question! Now it's New Year's day and some of the detail might not be perfect but the concept is.
Basically it all depends on where you fly and under which licencing authority you fly:
in the UK and the US with an old fashioned PPL you don't require type ratings under a certain MAUW (5700kilos or is it pounds?)
Eg, in RSA and Swazi and Mozambique - you need to be type rated for every aircraft type. That means a flight test and a "technical paper" to be passed for each.
Personally, especially for slightly more complex aircraft, I don't see that as a bad thing.
As a PPL many years ago, I did the KingAir 200 type rating with the late Val in Lanseria, RSA. I seem to recall that the best part of two weeks were spent on the books and the technical stuff was far harder than the flying!
Stik