If you're in the world of custom eLearning content development, you're most likely working with Subject Matter Experts (SMEs), and at least one project owner or stakeholder. That being the case, you are in danger of the ever-dreaded scope creep, as well as the common and equally terrifying "too many cooks in the kitchen" syndrome.
1. Scope Creep
Scope creep happens when expectations and resource demands are not properly managed. This means that it is on you to make sure the project's deadline, as well as any other milestone deadlines, are as clear as they can be. In establishing these deadlines, you have to be clear with your stakeholder and contributor team as to what your part is and what their part is. So, you collaboratively establish your scope and you make it very clear what the ramifications of any scope changes will be. You're essentially scaring your stakeholders into not expanding the scope, because they understand how onerous it is to change the project while it's in flight.
2. The "Too Many Cooks In The Kitchen" Syndrome
The "too many cooks in the kitchen" syndrome happens when your project has multiple SMEs and stakeholders, all of whom have opinions about how the project should turn out. You have to manage this situation by setting a very clear expectation that you will only take action on input from one single source of truth (SSOT), the Subject Matter Expert. This is your SME Prime. The SME Prime will act as a final reviewer of all input that comes in from other stakeholders and SMEs. So, if there are four other SMEs and each of them has their own opinion on how accurate or complete the topic-level content is, you don't have to decide who's right. Your SME Prime does that, and then feeds you the properly vetted content. This leaves topic-level decisions in the hands of the experts, and leaves you available to make creative, learner-obsessed decisions about the learning experience.
To sum up, scare people away from scope creep and designate a SME Prime. This keeps your project under control and inside of scope specifications.