Scope Creep
Projects can get out of hand easily.
The scope is how big the project is.
You need to make sure that you plan out the scope carefully at the beginning by carrying out a thorough investigation and analysis of the problems, its requirements and the specification. Failure to do so will lead to a poorly scoped project that can cause problems.
Make sure that any changes or additional features are fully thought out and the time in terms of new learning, building, testing and integrating them are fully investigated and evaluated before incorporating them into your project.
Just because someone tells you it's a good idea does not mean that it's essential. User feedback might tell you that the feature would have multiple benefits but it if means that you won't get the core features or the minimum viable product complete you probably shouldn't add that feature to the scope of the project.
You need to manage your project effectively with tools such as Kanban boards and sprints to keep on track and manage the scope of your project.
Reflecting on your work and evaluating regularly is key.