This paper draws attention to some of the unintended consequences of current planning directives, which not only obscure the true essence of complex endeavours, but may also inhibit the intellectual capabilities of planning teams because of their prescriptive and voluminous nature. In the Set-based Approach (SbA), we introduce five principles aimed at optimizing planning time and reducing the likelihood of making premature assumptions. SbA extends beyond the scope of military operational planning, offering a flexible planning philosophy that enables teams to deal more adeptly with uncertainty. The SbA concept has undergone informal testing during two pilot programs at the Swedish Defence University.