I have with very few (none that I know of False Positives)
smtpd_recipient_restrictions = permit_sasl_authenticated,
permit_mynetworks,
reject_invalid_hostname,
reject_unauth_destination,
check_policy_service inet:127.0.0.1:60000,
reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_unknown_recipient_domain,
reject_unauth_pipelining,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
# uncomment for realtime black list checks
reject_rbl_client zen.spamhaus.org,
reject_rbl_client bl.spamcop.net,
reject_rbl_client dnsbl.sorbs.net,
reject_rbl_client list.dsbl.org,
reject_rbl_client cbl.abuseat.org,
reject_rbl_client dul.dnsbl.sorbs.net,
permit
Also I use graylist (5 minute delay on first email from some one, but that is no hassle).
smtpd_recipient_restrictions = permit_sasl_authenticated,
permit_mynetworks,
reject_invalid_hostname,
reject_unauth_destination,
check_policy_service inet:127.0.0.1:60000,
reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_unknown_recipient_domain,
reject_unauth_pipelining,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
# uncomment for realtime black list checks
reject_rbl_client zen.spamhaus.org,
reject_rbl_client bl.spamcop.net,
reject_rbl_client dnsbl.sorbs.net,
reject_rbl_client list.dsbl.org,
reject_rbl_client cbl.abuseat.org,
reject_rbl_client dul.dnsbl.sorbs.net,
permit
Also I use graylist (5 minute delay on first email from some one, but that is no hassle).