When I was learning to fly, one of the things I learned is that the net effect of wind always negative. One might assume that a steady wind helps you when travelling in one direction and slows you down in the opposite direction, so that you break even. This is not true because, since the wind slows you down, it has longer to act on you.*
This is how I feel on a lot of the projects I have worked on during my career. During the course of a project a lot of “forces” such as opinions, meetings, new features, new requirements slow it down. Once the project is slowed, there is more time for other “forces” to slow it down …. and so on. I seen more than one project that have “run out of gas” after being slowed down for so long.
Agile development is a great way to avoid this situation in the coding world. In the design world, having hard constraints such as time, money and people also helps. As a matter of fact, some of the “slowest” projects had almost no constraints… One could almost infer that productivity is inversely proportional to resources.
Pilots always make sure they have enough fuel to get to their destination… as designers we should too.
*assuming the wind is constant in direction and velocity