Do I need spam assassin (spamd) ?

I guess spam assassin gets installed by default in CentOS - or I picked it 
and forgot about it :-) ?

I just noticed that several threads of spamd are running on my greylist / 
sendmail box. I don't have it configured, never see anything in the log 
about it, and I am not planning on using it.  Is is safe for me to stop it 
and set it to not restart on boot?

Thanks,
Dennis