diff --git a/src/collector.ml b/src/collector.ml
index a04cb5e..4d65bc5 100644
--- a/src/collector.ml
+++ b/src/collector.ml
@@ -10,12 +10,7 @@ open Types
 let dummy_span : span = Int64.min_int
 
 module type S = sig
-  val enabled : unit -> bool
-  (** Is the collector enabled? This should be extremely fast so that
-      the traced program can check it before creating any span or
-      message *)
-
-  val create_span :
+  val enter_span :
     ?__FUNCTION__:string -> __FILE__:string -> __LINE__:int -> string -> span
 
   val exit_span : span -> unit
diff --git a/src/tef/trace_tef.ml b/src/tef/trace_tef.ml
index bd697ee..2bd892f 100644
--- a/src/tef/trace_tef.ml
+++ b/src/tef/trace_tef.ml
@@ -214,8 +214,6 @@ let collector ~out () : collector =
     (** generator for span ids *)
     let span_id_gen_ = A.make 0
 
-    let enabled () = true
-
     (* queue of messages to write *)
     let events : event B_queue.t = B_queue.create ()
 
@@ -234,7 +232,7 @@ let collector ~out () : collector =
       else
         Thread.id (Thread.self ())
 
-    let create_span ?__FUNCTION__:_ ~__FILE__:_ ~__LINE__:_ name : span =
+    let enter_span ?__FUNCTION__:_ ~__FILE__:_ ~__LINE__:_ name : span =
       let span = Int64.of_int (A.fetch_and_add span_id_gen_ 1) in
       let tid = get_tid_ () in
       let time_us = now_us () in
diff --git a/src/trace.ml b/src/trace.ml
index 8110e53..fdd45a3 100644
--- a/src/trace.ml
+++ b/src/trace.ml
@@ -10,21 +10,21 @@ let collector : collector option A.t = A.make None
 let[@inline] enabled () =
   match A.get collector with
   | None -> false
-  | Some (module C) -> C.enabled ()
+  | Some _ -> true
 
-let[@inline] create_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name : span =
+let[@inline] enter_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name : span =
   match A.get collector with
   | None -> Collector.dummy_span
-  | Some (module C) -> C.create_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name
+  | Some (module C) -> C.enter_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name
 
 let[@inline] exit_span span : unit =
   match A.get collector with
   | None -> ()
   | Some (module C) -> C.exit_span span
 
-let with_collector_ (module C : Collector.S) ?__FUNCTION__ ~__FILE__ ~__LINE__
-    name f =
-  let sp = C.create_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name in
+let with_span_collector_ (module C : Collector.S) ?__FUNCTION__ ~__FILE__
+    ~__LINE__ name f =
+  let sp = C.enter_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name in
   match f sp with
   | x ->
     C.exit_span sp;
@@ -34,13 +34,13 @@ let with_collector_ (module C : Collector.S) ?__FUNCTION__ ~__FILE__ ~__LINE__
     C.exit_span sp;
     Printexc.raise_with_backtrace exn bt
 
-let[@inline] with_ ?__FUNCTION__ ~__FILE__ ~__LINE__ name f =
+let[@inline] with_span ?__FUNCTION__ ~__FILE__ ~__LINE__ name f =
   match A.get collector with
   | None ->
     (* fast path: no collector, no span *)
     f Collector.dummy_span
   | Some collector ->
-    with_collector_ collector ?__FUNCTION__ ~__FILE__ ~__LINE__ name f
+    with_span_collector_ collector ?__FUNCTION__ ~__FILE__ ~__LINE__ name f
 
 let[@inline] message ?__FUNCTION__ ~__FILE__ ~__LINE__ msg : unit =
   match A.get collector with
diff --git a/src/trace.mli b/src/trace.mli
index e437db6..2477b02 100644
--- a/src/trace.mli
+++ b/src/trace.mli
@@ -6,13 +6,17 @@ module Collector = Collector
 (** {2 Tracing} *)
 
 val enabled : unit -> bool
+(** Is there a collector?
+  
+    This is fast, so that the traced program can check it before creating
+    any span or message *)
 
-val create_span :
+val enter_span :
   ?__FUNCTION__:string -> __FILE__:string -> __LINE__:int -> string -> span
 
 val exit_span : span -> unit
 
-val with_ :
+val with_span :
   ?__FUNCTION__:string ->
   __FILE__:string ->
   __LINE__:int ->
diff --git a/test/t1.ml b/test/t1.ml
index 7080766..7bf599d 100644
--- a/test/t1.ml
+++ b/test/t1.ml
@@ -1,8 +1,8 @@
 let run () =
   for _i = 1 to 50 do
-    Trace.with_ ~__FUNCTION__ ~__FILE__ ~__LINE__ "outer.loop" @@ fun _sp ->
+    Trace.with_span ~__FUNCTION__ ~__FILE__ ~__LINE__ "outer.loop" @@ fun _sp ->
     for _j = 2 to 5 do
-      Trace.with_ ~__FILE__ ~__LINE__ "inner.loop" @@ fun _sp ->
+      Trace.with_span ~__FILE__ ~__LINE__ "inner.loop" @@ fun _sp ->
       Trace.messagef ~__FILE__ ~__LINE__ (fun k -> k "hello %d %d" _i _j)
     done
   done