What's the best approach for one, continuous scene that'll be ~3 minutes long.

[AndyThe94]

My animation needs to be continuous; no changes in shots or camera angles.
My plan is to just have everything in one project/timeline. Is that okay? Or is there a better way of doing it?

For example, do you think this animator had everything in one project file / timeline?

https://www.youtube.com/watch?v=KATpa_HJ3bQ

[cgmodeler]

it is always better to split your whole animation into clips, you can work with the clips as a general timeline on the project window and add audio as needed. You can render the project from there.

[slowtiger]

It highly depends on what's happening.

The example you posted is "many small actions in the same frame". I'd do it like this:
- first make a detailed animatic so I know which actions happen simultaneously
- create separate projects for each group of creatures, in larger size. Keep notes which frame they start and end in the master.
- animate these until I like their movements
- import the separate parts into a master file, adjust their timing
- go back to separate files with these changes, colour, export
- composite everything.

Careful planning is key. You'll notice that this example is not a simple "break down the whole into several clips" as the cations overlap each other.