Party studies are undergoing a refocusing towards personalisation and human agency. At the same time, persistent party system instability — both in younger democracies and, increasingly, in older ones — calls for new analytical approaches. The proliferation of new parties and the accelerating change in existing ones challenge our preconceived and often dichotomous notions of party novelty and continuity. Likewise, change, once obscured by the veneer of organisational stability, is becoming increasingly visible in established parties of long-standing European democracies. In response, we argue that a shift from an ‘organisational’ to an ‘evolutionary’ paradigm—focussing on people who make up the organisations—may be overdue. We outline two key dimensions of this shift: putting fluidity before stability and agents before institutions. We illustrate the underlying issues with examples drawn primarily from ‘advanced’ democracies to underscore that the challenges are far from unique to ‘new’ democracies.