A: 
Peter Turner
A: 

I prefer different modules to be hosted on different folders, then have a common folder for units that is shared among different modules, makes management easy. e.g

myClientServerApp:(parent) Client folder :(child) server filder (child) lib - (child)

Gath
+5  A: 

I don't think so. In fact, In more recent versions they've added features to the project manager to make it easier to deal with the fact that code is spread around different directories (such as the flatten directories option), so I think it is accepted that this is how many people organize their code.

I suspect it's more to do with projects growing organically over time, and whether anyone takes the time to tidy up.

Malcolm Groves
+2  A: 

I for one definitely do not put all the sources into one directory but rather keep them in groups that have something in common. e.g. I use subversion externals quite extensively (see http://www.dummzeuch.de/delphi/subversion/english.html , the section about externals).

Thomas Mueller
A: 

Back in DELPHI 7 I also had all files in one folder. It has easy for small projects, but very hard for med to big one. So I began to create a folder structure for all DELPHI projects small or big. Over the year I am trying to improve, this folder structure, and every new project I make a small improvement so that it is simpler, logical, and more organized. This day I am trying to make some parts of it sharable to several project. Its work in progress.

Jlouro