[Exim] verify = sender/callout

I am currently using verify = sender without the /callout option because the manual
says "it can add a lot of resource usage to the cost of verifying an address".

I am looking to see if most people have the callout switched on as it seems to me
that it would screen out a significant proportion of spam, saving the cost of
scanning.

Any advice?

Phil.
---------------------------------------
Phil Chambers (postmaster@???)
University of Exeter