PixInsight experts, lend me your expertise. So far, I've been saving everything, dark flats, flats, calibrated directory, cosmetized directory, etc. and the PixInsight project itself. I have a QHY600 60Mp camera, so these files and directories along with the project can be 6.5 GIG for each object. This doesn't include the lights or the darks.
What is really required for a multi-year project. Year to year I would like to just keep adding data to an object. I would think that only the Master Lights are required, is that correct? Therefore you would only need to keep the Master Lights for each filter from year to year and then combine Master Lights each year you wanted to add data to the object.