Lorenzo wrote:
  
> Hi list,
> 
> I'm already on the pd-list. I signed up to the pd-dev as I'm starting to
> look into some (simple) external development.
    
cool.
please note that pd-dev has the same netiquette as pd-list, that e.g.
asks you to not hijack another thread for your unrelated postings.
see http://puredata.info/community/lists/Netiquette#Threads
  
Wops, sorry about that :)
> 
> First, though, I thought it would be wise to ask when is it really worth
> to write an external vs using directly pd abstractions considering the
> various c/b? Is this in some way 'measurable'?
    
yes.
relate the time spent writing one solution (including learning to
actually do it plus doing big-fixes) to its relevant benefits (does it
work? what's the performance? is it portable? ...) and compare the
scalars you get for the various solutions :-)
  
Ok, but what I mean is also if there's some rule of thumb? My impression for example is that significant changes are only when dealing with signals or arrays (unless you're doing some really heavy heavy maths)?
Also, which would me a good method for measuring?

Lorenzo