When interwar Royal Navy cruisers would retire

Without the Second World War, when would Britain begin retiring its interwar cruisers?

Usually after about twenty to thirty years, putting 1920s ships into a 1940s retirement window and 1930s ships into the 1950s.

A twenty-to-thirty-year service life is a planning guide rather than a fixed retirement date. Cruisers ordered in the 1920s would normally begin disappearing during the 1940s, while 1930s construction would move toward retirement in the 1950s. Some older C- and D-class ships could remain for roughly thirty years when the navy still found uses for them. The continuing presence of several torpedo generations in the same fleet illustrates the same overlap: large navies retire ships and their associated systems gradually rather than in one clean changeover.