Every Monday you write a status report, and each time you attach the same four reference documents and restate the same background. What would remove that repetition?

The principle — the second time you attach the same file, you have outgrown the plain chat.

Why the key is correct — OpenAI describes projects as workspaces that keep everything related to a long-running effort in one place: grouped chats, uploaded reference files, and project instructions so ChatGPT stays on topic. A weekly report with fixed source documents is precisely that shape. Upload once, then start a fresh chat each Monday that can still draw on the material.

Why the others are wrong — one endless conversation degrades as unrelated weeks pile up in the same thread. Custom instructions are global, so a description of this report would leak into every unrelated chat you start. And memory holds context about you rather than files you can query.

Remember this — projects exist for repeated work. The signal is not how complex the task is; it is how many times you will come back to the same material.

Sources — OpenAI's Projects in ChatGPT article.