By Proactive Plan Managers – November 2025 One of the most common questions participants ask is: “Why did the NDIA approve one support but not another?” The answer often comes down to the phrase “reasonable and necessary.” Let’s break down what it actually means — and how you can use this knowledge to strengthen your plan and future reviews. 1. The Core Idea Under the NDIS Act, supports must be both reasonable  and necessary  to be funded. This means the NDIA looks at whether