Why Leander conversion studies began during construction

Why consider Ikara conversion proposals for the Leander class in 1963 while the ships were still being built?

Because modernization planning starts early, and the adaptable hull offered room to test future weapons and roles.

Conversion planning could begin while Leanders were still being built because the navy wanted to keep them up to date. The question specifically cites an Ikara conversion proposal from 1963. Later Leander conversions illustrate the usefulness of having enough adaptable ships to try different equipment and roles. Type 31 is compared with that intended model of building numbers and then developing future options through the class.