This position paper is written as a result of a number of emails and a presentation that have recently been circulated concerning the potential reduction of Development Flight Instrumentation (DFI) to be included on the Ares I-X flight test vehicle. A reduction in instrumentation has been proposed presumably to reduce project costs and relieve project schedule pressures. This proposal has generated a significant amount of discussion on both sides of the issue, primarily from those within the project. The intention here is to provide a perspective on this issue from outside the mainline project. Schuster, David M. Langley Research Center NASA/TM-2009-215909, NESC-RP-08-19/08-00454, L-19744, LF99-9312