How do you stop scope creep from ruining your weekend projects?

​It is so easy to fall into the trap of adding just one more feature once the core MVP starts working on Saturday night. what was supposed to be a simple two-screen utility suddenly turns into an ambitious platform with user dashboards and settings pages. i had to start writing down a strict one-page feature limit on a physical notepad before touching my code editor.

​how do you stop yourself from expanding a weekend build into a three-month monster project?