This is a tip I first picked up about thirty years ago (my God!) when I worked at Sun Microsystems and used the C shell fairly extensively. Fortunately there's no need to do so any more, as many of its more desirable features have been incorporated into bash.
There's nothing worse, even with tab-completion, than having to stab through a sequence of directories to find the location you want. If you're anything like me there are typically three or four main directories that I use for about 80% of the work that I do.
The CDPATH environment variable works pretty much like your PATH setting, except that instead of being used to locate executables it's used to locate directories. It comes into play when you issue a cd or pushd command. So, for example, on my personal machine my .bash_profile contains the following line:
So when I try to change to a new directory the shell first looks in the current directory (it can cause real confusion if you don't look there first), then in my Projects directory, then in its Python sub-directory. So the command
takes me to my ~/Projects/Python/PytDj project directory with no need to specify the path. I estimate this saves me at least a minute a day, so over thirty years it's saved me a substantial amount of time. Try it, and see what you think.