I'm updating a website and every time I get an archive of the files I need to update, I end up copying the lot over and wiping out my creation dates. It doesn't matter right now in the sense that the site isn't live, but even so I end up copying over a gig where I might only need to copy megabytes over. It can't just be done on the date, because the files in the archive all get today's date. I have been told about a tool called rsync, but I'm not sure what to do with it.
Maybe you're looking for a solution using Directory Opus, but Beyond Compare from Scooter Software will compare files in a folder with files in an archive as if it were another folder. Beyond Compare allows a lot of control over the way the files are compared.
Edit: Should have added that BC can then copy newer files, for example, from one side to the other.
I'm going from a local archive to a temp folder, then using Filezilla to copy that up to the sftp server. I see that Beyond Compare's Pro version actually has built-in sftp, so that might be the magic bullet I need. Thanks!