Setup each project in a separate file or all projects in one file?

Hello,
I am new to Gannt Project.
Would you rather recommend to setup each project in a separate file or all project in one file?
I think having all projects in one file could be handy for overall overview. Are there any disadvantages to this approach?

I usually use 1 file for each project if it is a working project plan with tasks and allocations. I then have a sepperate file for our executive management and directors that shows all projects on a single time line (we build boats) so there is one file ofr each boat and then a sepperate file showing status of all boats in the pipeline. hope that helps

@SteveBKK:
I have similar work to manage. If you have one file for every project (for each boat in your case), how can you get a file that shows all projects on a single timeline? Manually?