diff --git a/collector/dfsr.go b/collector/dfsr.go
index b94ed8d6..2573ca94 100644
--- a/collector/dfsr.go
+++ b/collector/dfsr.go
@@ -4,12 +4,14 @@ package collector
 
 import (
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
 var dfsrEnabledCollectors = kingpin.Flag("collectors.dfsr.sources-enabled", "Comma-seperated list of DFSR Perflib sources to use.").Default("connection,folder,volume").String()
 
 func init() {
+	log.Info("dfsr collector is in an experimental state! Metrics for this collector have not been tested.")
 	// Perflib sources are dynamic, depending on the enabled child collectors
 	var perflibDependencies []string
 	for _, source := range expandEnabledChildCollectors(*dfsrEnabledCollectors) {
diff --git a/collector/smtp.go b/collector/smtp.go
index df236edc..70eb6b3a 100644
--- a/collector/smtp.go
+++ b/collector/smtp.go
@@ -11,6 +11,7 @@ import (
 )
 
 func init() {
+	log.Info("smtp collector is in an experimental state! Metrics for this collector have not been tested.")
 	registerCollector("smtp", NewSMTPCollector, "SMTP Server")
 }
 
diff --git a/docs/collector.dfsr.md b/docs/collector.dfsr.md
index 9369048d..e018f107 100644
--- a/docs/collector.dfsr.md
+++ b/docs/collector.dfsr.md
@@ -2,6 +2,8 @@
 
 The dfsr collector exposes metrics for [DFSR](https://docs.microsoft.com/en-us/windows-server/storage/dfs-replication/dfsr-overview).
 
+**Collector is currently in an experimental state and testing of metrics has not been undertaken.** Feedback on this collector is welcome.
+
 |||
 -|-
 Metric name prefix  | `dfsr`