diff --git a/bash_it.sh b/bash_it.sh
index 00a1bcea..ddc02b70 100755
--- a/bash_it.sh
+++ b/bash_it.sh
@@ -51,8 +51,6 @@ if [[ -n "${BASH_IT_THEME:-}" ]]; then
 	source "${BASH_IT}/themes/githelpers.theme.bash"
 	BASH_IT_LOG_PREFIX="themes: p4helpers: "
 	source "${BASH_IT}/themes/p4helpers.theme.bash"
-	BASH_IT_LOG_PREFIX="themes: command_duration: "
-	source "${BASH_IT}/themes/command_duration.theme.bash"
 	BASH_IT_LOG_PREFIX="themes: base: "
 	source "${BASH_IT}/themes/base.theme.bash"
 
diff --git a/clean_files.txt b/clean_files.txt
index 36bdc08c..e52d5a9f 100644
--- a/clean_files.txt
+++ b/clean_files.txt
@@ -78,6 +78,7 @@ completion/available/wpscan.completion.bash
 # libraries
 lib/appearance.bash
 lib/colors.bash
+lib/command_duration.bash
 lib/helpers.bash
 lib/history.bash
 lib/log.bash
@@ -155,7 +156,6 @@ themes/bobby-python
 themes/brainy
 themes/brunton
 themes/candy
-themes/command_duration.theme.bash
 themes/easy
 themes/essential
 themes/githelpers.theme.bash
diff --git a/lib/command_duration.bash b/lib/command_duration.bash
new file mode 100644
index 00000000..bc0cca8e
--- /dev/null
+++ b/lib/command_duration.bash
@@ -0,0 +1,56 @@
+# shellcheck shell=bash
+#
+# Functions for measuring and reporting how long a command takes to run.
+
+: "${COMMAND_DURATION_START_SECONDS:=${EPOCHREALTIME:-$SECONDS}}"
+: "${COMMAND_DURATION_ICON:=🕘}"
+: "${COMMAND_DURATION_MIN_SECONDS:=1}"
+
+function _command_duration_pre_exec() {
+	COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
+}
+
+function _dynamic_clock_icon {
+	local -i clock_hand=$(((${1:-${SECONDS}} % 12) + 90))
+	printf -v 'COMMAND_DURATION_ICON' '%b' "\xf0\x9f\x95\x$clock_hand"
+}
+
+function _command_duration() {
+	[[ -n "${BASH_IT_COMMAND_DURATION:-}" ]] || return
+
+	local command_duration=0 command_start="${COMMAND_DURATION_START_SECONDS:-0}"
+	local -i minutes=0 seconds=0 deciseconds=0
+	local -i command_start_seconds="${command_start%.*}"
+	local -i command_start_deciseconds=$((10#${command_start##*.}))
+	local current_time="${EPOCHREALTIME:-$SECONDS}"
+	local -i current_time_seconds="${current_time%.*}"
+	local -i current_time_deciseconds="$((10#${current_time##*.}))"
+
+	if [[ "${command_start_seconds:-0}" -gt 0 ]]; then
+		# seconds
+		command_duration="$((current_time_seconds - command_start_seconds))"
+
+		if ((current_time_deciseconds >= command_start_deciseconds)); then
+			deciseconds="$((current_time_deciseconds - command_start_deciseconds))"
+		else
+			((command_duration -= 1))
+			deciseconds="$((10 - (command_start_deciseconds - current_time_deciseconds)))"
+		fi
+	else
+		command_duration=0
+	fi
+
+	if ((command_duration > 0)); then
+		minutes=$((command_duration / 60))
+		seconds=$((command_duration % 60))
+	fi
+
+	_dynamic_clock_icon "${command_duration}"
+	if ((minutes > 0)); then
+		printf "%s%s%dm %ds" "${COMMAND_DURATION_ICON:-}" "${COMMAND_DURATION_COLOR:-}" "$minutes" "$seconds"
+	elif ((seconds >= COMMAND_DURATION_MIN_SECONDS)); then
+		printf "%s%s%d.%01ds" "${COMMAND_DURATION_ICON:-}" "${COMMAND_DURATION_COLOR:-}" "$seconds" "$deciseconds"
+	fi
+}
+
+_bash_it_library_finalize_hook+=("safe_append_preexec '_command_duration_pre_exec'")
diff --git a/plugins/available/cmd-returned-notify.plugin.bash b/plugins/available/cmd-returned-notify.plugin.bash
index d9be5e4e..88c07722 100644
--- a/plugins/available/cmd-returned-notify.plugin.bash
+++ b/plugins/available/cmd-returned-notify.plugin.bash
@@ -2,15 +2,15 @@
 cite about-plugin
 about-plugin 'Alert (BEL) when process ends after a threshold of seconds'
 
-precmd_return_notification() {
-	export LAST_COMMAND_DURATION=$(($(date +%s) - ${LAST_COMMAND_TIME:=$(date +%s)}))
-	[[ ${LAST_COMMAND_DURATION} -gt ${NOTIFY_IF_COMMAND_RETURNS_AFTER:-5} ]] && echo -e "\a"
-	export LAST_COMMAND_TIME=
+function precmd_return_notification() {
+	local command_start="${COMMAND_DURATION_START_SECONDS:=0}"
+	local current_time="${EPOCHREALTIME:-$SECONDS}"
+	local -i command_duration="$((${current_time%.*} - ${command_start%.*}))"
+	if [[ "${command_duration}" -gt "${NOTIFY_IF_COMMAND_RETURNS_AFTER:-5}" ]]; then
+		printf '\a'
+	fi
+	return 0
 }
 
-preexec_return_notification() {
-	[[ -z "${LAST_COMMAND_TIME}" ]] && LAST_COMMAND_TIME=$(date +%s)
-}
-
-precmd_functions+=(precmd_return_notification)
-preexec_functions+=(preexec_return_notification)
+safe_append_prompt_command 'precmd_return_notification'
+safe_append_preexec '_command_duration_pre_exec'
diff --git a/test/plugins/cmd-returned-notify.plugin.bats b/test/plugins/cmd-returned-notify.plugin.bats
index ca40f3b5..04edad95 100644
--- a/test/plugins/cmd-returned-notify.plugin.bats
+++ b/test/plugins/cmd-returned-notify.plugin.bats
@@ -3,46 +3,39 @@
 load "${MAIN_BASH_IT_DIR?}/test/test_helper.bash"
 
 function local_setup_file() {
-  setup_libs "preexec" #"command_duration"
+  setup_libs "command_duration"
   load "${BASH_IT?}/plugins/available/cmd-returned-notify.plugin.bash"
 }
 
 @test "plugins cmd-returned-notify: notify after elapsed time" {
-    export NOTIFY_IF_COMMAND_RETURNS_AFTER=0
-    export LAST_COMMAND_TIME=$(date +%s)
-    sleep 1
-    run precmd_return_notification
-    assert_success
-    assert_output $'\a'
+	export NOTIFY_IF_COMMAND_RETURNS_AFTER=0
+	export COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
+	sleep 1
+	run precmd_return_notification
+	assert_success
+	assert_output $'\a'
 }
 
 @test "plugins cmd-returned-notify: do not notify before elapsed time" {
-    export NOTIFY_IF_COMMAND_RETURNS_AFTER=10
-    export LAST_COMMAND_TIME=$(date +%s)
-    sleep 1
-    run precmd_return_notification
-    assert_success
-    assert_output $''
+	export NOTIFY_IF_COMMAND_RETURNS_AFTER=10
+	export COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
+	sleep 1
+	run precmd_return_notification
+	assert_success
+	assert_output $''
 }
 
-@test "plugins cmd-returned-notify: preexec no output" {
-    export LAST_COMMAND_TIME=
-    run preexec_return_notification
-    assert_success
-    assert_output ""
+@test "lib command_duration: preexec no output" {
+	export COMMAND_DURATION_START_SECONDS=
+	run _command_duration_pre_exec
+	assert_success
+	assert_output ""
 }
-
-@test "plugins cmd-returned-notify: preexec no output env set" {
-    export LAST_COMMAND_TIME=$(date +%s)
-    run preexec_return_notification
-    assert_failure
-    assert_output ""
-}
-
-@test "plugins cmd-returned-notify: preexec set LAST_COMMAND_TIME" {
-    export LAST_COMMAND_TIME=
-    assert_equal "${LAST_COMMAND_TIME}" ""
-    NOW=$(date +%s)
-    preexec_return_notification
-    assert_equal "${LAST_COMMAND_TIME}" "${NOW}"
+@test "lib command_duration: preexec set COMMAND_DURATION_START_SECONDS" {
+	export COMMAND_DURATION_START_SECONDS=
+	assert_equal "${COMMAND_DURATION_START_SECONDS}" ""
+	NOW="${EPOCHREALTIME:-$SECONDS}"
+	_command_duration_pre_exec
+	# We need to make sure to account for nanoseconds...
+	assert_equal "${COMMAND_DURATION_START_SECONDS%.*}" "${NOW%.*}"
 }
diff --git a/test/test_helper.bash b/test/test_helper.bash
index 919e7559..bffb59ed 100644
--- a/test/test_helper.bash
+++ b/test/test_helper.bash
@@ -57,7 +57,7 @@ function common_setup_file() {
 function setup_libs() {
 	local lib
 	# Use a loop to allow convenient short-circuiting for some test files
-	for lib in "log" "utilities" "helpers" "search" "preexec" "colors"; do
+	for lib in "log" "utilities" "helpers" "search" "preexec" "colors" "command_duration"; do
 		load "${BASH_IT?}/lib/${lib}.bash" || return
 		# shellcheck disable=SC2015 # short-circuit if we've reached the requested library
 		[[ "${lib}" == "${1:-}" ]] && return 0 || true
diff --git a/themes/command_duration.theme.bash b/themes/command_duration.theme.bash
deleted file mode 100644
index cf91785c..00000000
--- a/themes/command_duration.theme.bash
+++ /dev/null
@@ -1,69 +0,0 @@
-# shellcheck shell=bash
-
-if [ -z "$BASH_IT_COMMAND_DURATION" ] || [ "$BASH_IT_COMMAND_DURATION" != true ]; then
-	_command_duration() {
-		echo -n
-	}
-	return
-fi
-
-# Define tmp dir and file
-COMMAND_DURATION_TMPDIR="${TMPDIR:-/tmp}"
-COMMAND_DURATION_FILE="${COMMAND_DURATION_FILE:-$COMMAND_DURATION_TMPDIR/bashit_theme_execution_$BASHPID}"
-
-COMMAND_DURATION_ICON=${COMMAND_DURATION_ICON:-'  '}
-COMMAND_DURATION_MIN_SECONDS=${COMMAND_DURATION_MIN_SECONDS:-'1'}
-
-trap _command_duration_delete_temp_file EXIT HUP INT TERM
-
-_command_duration_delete_temp_file() {
-	if [[ -f "$COMMAND_DURATION_FILE" ]]; then
-		rm -f "$COMMAND_DURATION_FILE"
-	fi
-}
-
-_command_duration_pre_exec() {
-	date +%s.%1N > "$COMMAND_DURATION_FILE"
-}
-
-_command_duration() {
-	local command_duration command_start current_time
-	local minutes seconds deciseconds
-	local command_start_sseconds current_time_seconds command_start_deciseconds current_time_deciseconds
-	current_time=$(date +%s.%1N)
-
-	if [[ -f "$COMMAND_DURATION_FILE" ]]; then
-		command_start=$(< "$COMMAND_DURATION_FILE")
-		command_start_sseconds=${command_start%.*}
-		current_time_seconds=${current_time%.*}
-
-		command_start_deciseconds=$((10#${command_start#*.}))
-		current_time_deciseconds=$((10#${current_time#*.}))
-
-		# seconds
-		command_duration=$((current_time_seconds - command_start_sseconds))
-
-		if ((current_time_deciseconds >= command_start_deciseconds)); then
-			deciseconds=$(((current_time_deciseconds - command_start_deciseconds)))
-		else
-			((command_duration -= 1))
-			deciseconds=$((10 - ((command_start_deciseconds - current_time_deciseconds))))
-		fi
-		command rm "$COMMAND_DURATION_FILE"
-	else
-		command_duration=0
-	fi
-
-	if ((command_duration > 0)); then
-		minutes=$((command_duration / 60))
-		seconds=$((command_duration % 60))
-	fi
-
-	if ((minutes > 0)); then
-		printf "%s%s%dm %ds" "$COMMAND_DURATION_ICON" "$COMMAND_DURATION_COLOR" "$minutes" "$seconds"
-	elif ((seconds >= COMMAND_DURATION_MIN_SECONDS)); then
-		printf "%s%s%d.%01ds" "$COMMAND_DURATION_ICON" "$COMMAND_DURATION_COLOR" "$seconds" "$deciseconds"
-	fi
-}
-
-preexec_functions+=(_command_duration_pre_exec)