Whether you wish to split large RTF files into several smaller files is up to you. It has no effect on the output document whether you are generating recompilable source code or print-ready documents. Here are the issues to be considered:
Processor speed and system memory
The less RAM you have and the slower the processor on the system, the greater the speed increase in loading documents composed of several smaller files. RTF files take much longer to load than standard .DOC format word processing documents. If you expect to load the file once, print it and erase it forever, then a bit of a wait while the file loads might not be a major problem. But if you want to perform extensive editing on a large output file prior to printing, then it will be to your advantage to break this file up into parts and merge it into one document only when you're finished editing.
How large is the file you are converting?
There is no easy way to determine how large an RTF file you will generate from a given compiled file. A 500KB helpfile might generate a print-ready output file as small as 100KB depending on how it was created, or it could produce a document as large as 10MB if it used a lot of graphics and was compiled using data compression options.
On average, though, you can expect to generate two to three bytes of data for every byte of size in the original compiled file.
Issues relating to split files
When generating print-ready documents, Help to RTF tries to start new files at the point at which a specific topic ends so you have complete sections to work with in each output file. The sizes of the split files can vary depending on whether images are embedded in the RTF or saved to disk as separate embeddable files. Generally speaking Help to RTF tries to insure that split output files are small enough to be comfortably edited on systems with as little as 4MB of memory.
When generating recompilable source code, keep in mind that Help to RTF won't split the document up in mid-topic, but also remember that if you merge the RTF into another project you will need to reference more than one .RTF document in the project setup or .HPJ file in order to insure all source text and image references are included in the new project.