[exim] helo checks

Hi

Until now, I thought my exim would check helo strings.
However I just recognized, that my server does not require helo at all.
I read some web pages and the docs about helo checks, but there was no clear
solution.

So, how do you do helo check? Or, are you doing them at all?
What is regarded as "good practice" ?

Regards,
Steffen