I don’t know about this limit but having 255+ sub-documents is an indication of a lack of logical organisation of the document. Using master+sub-documents is legitimate for
- a really huge document with medium-sized sub-documents (meaning: don’t use the feature for small sub-documents as you’ll make things difficult to manage and put too much strain on Writer)
- a document using parts shared with other documents
Other than these two cases, go for a usual document (Writer handles quite well documents up to ~1000 pages provided you structure it rigorously both in its ouline and styling = avoid direct formatting)
Yes, lists and chapter numbering can’t have more then 10 levels. If you fancy to need more, question your structuring. Perhaps you mixed outline with lists. Anyway, from a reader’s point of view, it is difficult to grasp meaning with too many levels.
This limit is independent of document organisation, usual document or master+sub-documents. In the latter case, remember that the final document is synthesised by the master. Don’t try to outsmart Writer by splitting you “monster levels” between master and subs as the final job is done by the master.
Not at all. Master is an elegant way to organise a complex huge document but the feature must be used wisely. As already said, Writer can handle “comfortably” documents up to ~1000 pages. So there is no point to embark for difficulties with a master if there is no real need for it.
Master+subs are at their best when subs come from various authors. It is an easy way to merge into a single report. But authors must have followed a strict styling discipline otherwise the document will look heterogeneous.
The fact that not that many people use it is motivated by the added complexity in formatting and also the scarcity of cases where it is required. Computers have drastically boosted their performance in recent years and Writer has also evolved. It can now handle documents which were not possible in the recent past.