I've been brought into projects as a senior developer to try to revitalise the project and get it back on track after a catastrophe or a failure to produce, and

I've been brought into projects as a senior developer to try to revitalise the project and get it back on track after a catastrophe or a failure to produce, and I always recommend, straight off the bat, put down your tools and go be a user for a day/week/month, until you understand what you're doing and have a stable point around which to orient the rest of the chaos in the project. It has always worked. Software projects (hardware too of course) get off the rails when too much time is spent in the woods and not enough time enjoying the trees. Get out there and use what you've made - you'll see what you need to do after assuming the perspective of a user for a while ..