diff --git a/roles/common/tasks/tarsnap.yml b/roles/common/tasks/tarsnap.yml
index 1f1a0ef..866a59f 100644
--- a/roles/common/tasks/tarsnap.yml
+++ b/roles/common/tasks/tarsnap.yml
@@ -1,12 +1,21 @@
 ---
 - name: Add Tarsnap apt mirror
   template: src=tarsnap_sources.list.j2 dest=/etc/apt/sources.list.d/tarsnap.list owner=root group=root mode=0644
+  register: add_tarsnap_apt_repository
   when: ansible_architecture != 'armv7l'
 
 - name: Add GPG key for Tarsnap
   apt_key: id=0x70BD6C50E82A9D99 url=https://pkg.tarsnap.com/tarsnap-deb-packaging-key.asc state=present
+  register: add_tarsnap_apt_key
   ignore_errors: yes
 
+- name: Update apt cache
+  apt:
+    update_cache: yes
+  when:
+    add_tarsnap_apt_key is changed or
+    add_tarsnap_apt_repository is changed
+
 - name: Install tarsnap
   apt: pkg=tarsnap update_cache=yes
 
diff --git a/roles/mariadb/tasks/main.yml b/roles/mariadb/tasks/main.yml
index c9b1426..a070ba8 100644
--- a/roles/mariadb/tasks/main.yml
+++ b/roles/mariadb/tasks/main.yml
@@ -1,12 +1,21 @@
 ---
 - name: Add GPG key for MariaDB repo
   apt_key: id=0x177F4010FE56CA3336300305F1656F24C74CD1D8 url=https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x177F4010FE56CA3336300305F1656F24C74CD1D8
+  register: add_mariadb_apt_key
   tags: mariadb, packages
 
 - name: Add MariaDB 10.3 repo
   template: src=mariadb.list.j2 dest=/etc/apt/sources.list.d/mariadb.list owner=root group=root mode=0644
+  register: add_mariadb_apt_repository
   tags: mariadb, packages
 
+- name: Update apt cache
+  apt:
+    update_cache: yes
+  when:
+    add_mariadb_apt_key is changed or
+    add_mariadb_apt_repository is changed
+
 - name: Install mariadb-server
   apt: name={{ item }} state=present update_cache=yes
   loop:
diff --git a/roles/nginx/tasks/main.yml b/roles/nginx/tasks/main.yml
index f6f8eb0..dacf9c4 100644
--- a/roles/nginx/tasks/main.yml
+++ b/roles/nginx/tasks/main.yml
@@ -1,12 +1,21 @@
 ---
 - name: Add nginx.org apt signing key
   apt_key: id=0x573BFD6B3D8FBC641079A6ABABF5BD827BD9BF62 url=https://nginx.org/keys/nginx_signing.key state=present
+  register: add_nginx_apt_key
   tags: nginx, packages
 
 - name: Add nginx.org repo
   template: src=nginx_org_sources.list.j2 dest=/etc/apt/sources.list.d/nginx_org_sources.list owner=root group=root mode=0644
+  register: add_nginx_apt_repository
   tags: nginx, packages
 
+- name: Update apt cache
+  apt:
+    update_cache: yes
+  when:
+    add_nginx_apt_key is changed or
+    add_nginx_apt_repository is changed
+
 - name: Install nginx
   apt: pkg=nginx update_cache=yes state=present
   tags: nginx, packages