Should I install X11 on my Mac Book Pro? I have recently purchased a Mac Book Pro (Mavericks 10.9.3) and I'd like to run Inkscape.  After researching the subject I see that I need to install X11, however I don't want to do this if X11 is going to run continuously and chew up CPU resources.  (Inkscape is the only X11 app I am likely to use, I think).

So, if I install X11, will it run whenever the machine is in use?  Or only when an X11 app (such as Inkscape) is running.  And are there other downsides/complications to running X11?
If you install the X11 subsystem, it will only run when you have an X11 program running.

Much the same as when installing the JVM - that will only run when you run a Java program.