The A2 Optimized Plugin is great to have.

This A2 Optimized plugin has the optimized presets for the W3 Total Cache plugin which A2 hosting recommends people use on their shared server, although this is not strictly necessary. If desired, the A2 Optimized plugin presets can be manually changed in the W3 total Cache plugin. When I first activated the A2 Optimized plugin, it warned me the iThemes Security plugin was incompatible with it (I.e. W3 Total Cache plugin). I had previously read that deactivating the ‘Hide backend’ option in the iThemes Security plugin would solve the incompatibility issue with W3 total Cache. So I did this and then used the ‘WPS Hide Login’ plugin to hide the backend which iThemes had previously done. Unfortunately this did not solve the incompatibility issue and I got locked out of my website. (This had previously happened to me when using the iThemes Security plugin with another web host and might have been an incompatibility issue with the WP Super Cache plugin and iThemes). So I swapped the iThemes Security plugin for the Sucuri free WordPress upload version and this solved all the plugin incompatibility issues I was having. A2 Hosting also have a free site scanner in their Lite package which although is not as efficient as the paid for Sucuri scanner, it is never the less reassuring to have.
To summarize, the A2 optimize plugin did all the hard work of setting up the W3 total Cache plugin for me and let me know there was an incompatibility issue with the iThemes Security plugin. This has saved me a lot of time and energy and I am truly grateful for this.