philosophical question about frequent saving of files

Is it OK for a program/IDE to automatically/frequently save edited docs?

Traditional programmer editors on unix have buffers and require explicit
saving. None of them ever instituted auto-save (that I know of).
So by one measure automatically saving a file to disk will violate
many a programmers expectation. 
OTOH, in order to smooth flow IDEs will most commonly save
files to disk before doing a build w/o asking the user any questions.
Adding in on the fly compilation, fix and continue and all that the
trend seems to be to _hide_ the fact that there is a continuum of
	file in buffer
	file saved to  disk
	file compiled to .class/.o
	file linker into .jar/a.out
	file run as a process
	file as a proxy in debugger symbol table
by that measure there should be no distinction between file in buffer and
file saved to disk which would argue that an IDE should save anytime
it chooses.

The practical actual reason I'm pondering this question is that 
I need the external debugger engine to detect out-of-date src and
oobject code and one way would be to have the IDE save src file edits 
at crucial times.

Personally I know that I subconsciously save my vi buffers often and
almost randomly apparently sticking to the second model. while others
might be much more deliberate and aware of theur buffer saves.

This almos might matter depending on what you're using.
Could it be for example that if you're interacting with the bult-in
editor you have one expectation while if you're interacting with the
external emacs/vi you have a different expectation?