how much memory?

[Joe Corneli <jcorneli@math.utexas.edu>]

Sorry about the potential lack of specificity of this question,
but how much memory should I assume Emacs has available to it?

If I'm reading files into buffers or storing them as strings or
something like this, how many characters can I store before I should
expect a crash or other weird behavior.

I've seen the "Memory Usage" node in the elisp manual, but can you
give suggestions on how to extrapolate from there to answer the above
question?

I realize this may depend on hardware and configuration details, but
what's the general algorithm?