Should I share Document Root with my other hosted websites?

[concorde7]

I am migrating/consolidating about 10 domains to a new host that were scattered to different registrars and 3 of these URL's will be independent websites for 2 separate businesses and 1 personal site. The rest of the domains are just there to have it all consolidated until they will be used/redirected or whatever. When adding these new domains (Creating Domain) in c-panel should I share document root with the 'main domain' or is this a bad idea? Is there a reason not to or to do so? Are there lop-sided security risks one way or the other or is this just a matter of preference?

[GigaWatt]

I use a separate directory for each domain and subdomain. It makes things more tidy and you can always find your way around , not to mention changing permissions on one domain will affect a bunch of other domains when they share the same root directory.