I have the same issue.
Why doesn't the file size reduce when I delete objects?
I have a cathedral in a SU file and the document size is 1.1 GB. In fact most of my files are around the 850-900meg range. And yes SU does crash a lot and waste vast amount of my time waiting for anything to reload.
I've copied it and deleted 90% of the building and I still end up with the same size file. What am I doing wrong?? Please help
Andrew