diff --git a/scripts/_common.sh b/scripts/_common.sh
index 3e6b5e1..c48820f 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -43,6 +43,22 @@ fix_permissions() {
 }
 
 
+install_apt_dependencies() {
+    sudo apt-get install -y -qq python-dev python-virtualenv supervisor libmysqlclient-dev
+}
+
+create_unix_user() {
+    sudo mkdir -p /opt/yunohost
+    sudo useradd ihatemoney -d /opt/yunohost/ihatemoney/ --create-home || ynh_die "User creation failed"
+}
+
+create_system_dirs() {
+    sudo install -o ihatemoney -g ihatemoney -m 755 -d \
+         /var/log/ihatemoney \
+         /etc/ihatemoney
+    sudo mkdir -p /opt/yunohost
+}
+
 ### Backported helpers (from testing)
 
 
diff --git a/scripts/install b/scripts/install
index e7177a6..8cf1987 100755
--- a/scripts/install
+++ b/scripts/install
@@ -56,12 +56,9 @@ trap exit_properly ERR
 ynh_app_setting_set $app domain $domain
 ynh_app_setting_set $app is_public "$is_public"
 
-# Install debian packages dependencies
-sudo apt-get install -y -qq python-dev python-virtualenv supervisor libmysqlclient-dev
+install_apt_dependencies
 
-# Create the dedicated user
-sudo mkdir -p /opt/yunohost
-sudo useradd ihatemoney -d /opt/yunohost/ihatemoney/ --create-home
+create_unix_user
 
 # Install source
 fetch_and_extract /opt/yunohost/ihatemoney/src/ ihatemoney
@@ -74,9 +71,7 @@ sudo /opt/yunohost/ihatemoney/venv/bin/pip install gunicorn>=19.3.0 MySQL-python
 # Fix permissions
 fix_permissions /opt/yunohost/ihatemoney/src
 
-# Create various dirs
-sudo install -o ihatemoney -g ihatemoney -m 755 \
-     -d /var/log/ihatemoney /etc/ihatemoney
+create_system_dirs
 
 # Configure gunicorn
 sudo install -o ihatemoney -g ihatemoney -m 644 \
diff --git a/scripts/restore b/scripts/restore
index 770aad3..9a358eb 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -46,12 +46,9 @@ test -f $gunicorn_conf_path && ynh_die \
 "The Gunicorn configuration already exists at '${gunicorn_conf_path}'.
  You should safely delete it before restoring this app."
 
-# Install debian packages dependencies
-sudo apt-get install -y -qq python-dev python-virtualenv supervisor libmysqlclient-dev
+install_apt_dependencies
 
-# Create the dedicated user
-sudo mkdir -p /opt/yunohost/
-sudo useradd ihatemoney -d /opt/yunohost/ihatemoney/ --create-home
+create_unix_user
 
 # Restore the app files
 sudo cp -a ./install_dir/. "$INSTALL_DIR"
@@ -61,9 +58,7 @@ fix_permissions ${INSTALL_DIR}/src
 ynh_mysql_create_db "$dbname" "$dbuser" "$dbpass"
 ynh_mysql_connect_as "$dbuser" "$dbpass" "$dbname" < ./db.sql
 
-# Create various dirs
-sudo install -o ihatemoney -g ihatemoney -m 755 \
-     -d /var/log/ihatemoney /etc/ihatemoney
+create_system_dirs
 
 # Restore settings
 sudo cp -a "conf/nginx.conf" "$nginx_conf_path"