--- Quote Start ---
Am using Quartus and SOPC Builder and have created a custom component. If I modify the code associated with the custom component, do I need to edit it in the component editor, regenerate the SOPC builder file and then compile in Quartus? Or will compiling in Quartus take care of it?
--- Quote End ---
If you change the ports on the component, eg., add a new input or output, then you need to edit the _hw.tcl file to export the new signal or edit the Avalon-MM signals (eg., wider address bus).
If you are just changing the implementation/internals of the component, then just re-synthesize.
Cheers,
Dave