diff --git a/R/api.R b/R/api.R
index 75fc64f..3c3bb37 100644
--- a/R/api.R
+++ b/R/api.R
@@ -179,7 +179,7 @@ format.profile_data <- function(x, ...) {
 #' }
 dm_from_profile <- function(x) {
   stopifnot(inherits(x, "profile_data"))
-  stopifnot(rlang::is_installed("dm"))
+  check_installed("dm")
 
   samples <- x$samples
   locations <- x$locations
diff --git a/R/proto.R b/R/proto.R
index abf5ec1..9149fbf 100644
--- a/R/proto.R
+++ b/R/proto.R
@@ -1,8 +1,5 @@
 provide_proto <- function() {
-  if (!is_installed("RProtoBuf")) {
-    abort("Package RProtoBuf is required to read pprof files.")
-  }
-
+  check_installed("RProtoBuf")
   install_proto_files()
 }