Plesk Advisor is an extension for Plesk Panel that comes pre-installed with most Plesk versions. We have disabled it on our shared servers so as to ensure the recommendations don't confuse our customers. However those using their own VPS with Plesk may have it installed and activated. Here's a quick overview of the tool and how to treat its recommendations.
Plesk's advisor is generally quite good; it helps demystify a lot of server administration! That said, it's also a sales tool which will try to suggest things that cost money and/or don't provide as much benefit as it may lean to suggest. You can see how slanted it is towards sales by looking at the "score" these paid items provide!
It's first two common major recommendations are ImmunifyAV and Scheduled Backups. These, as a whole, are fine recommendations.
ImmunifyAV: Immunify costs a fair bit of money - more than we've found it to be worth in our testing. If you are not and/or do not intend to be diligent about keeping things updated (CMS like WordPress, plugins, themes, etc) then it would likely be of more value, but WordPress et al are great at security if you keep them updated.
Scheduled Backups: For Scheduled Backups, you can either backup using Plesk Backup or Installatron. If you opt for the latter, Plesk Advisor will not know about this and therefore it will always recommend you set up Plesk backups.
Security, PHP Versions, SEO & Updates: Recommendations to go through your sites and use more current PHP versions is absolutely a solid recommendation. If you do have sites that aren't using SSL, that's a good one to fix!
Performance: the only one I'd look at is possibly the PageSpeed extension because it's not trying to sell you anything - just giving you an easy-to-access PageSpeed score.
Overall, it's a good tool, but needs to be parsed as a sales tool and an advisor. Like how car salespeople are often called "advisors", too.
