I found this great WordPress maintenance checklist that details the key steps you need to follow to keep your website robust and healthy.
Although a critical first step, keeping your site working well requires more just updating your plugins and your version of WordPress. A full site maintenance audit should be done every couple of months to ensure that your visitors continue to have a great user experience.
Maintaining your WordPress website also improves your SEO score and maximizes your chances that your site will not go down.
Contact me if you would like me to review your site and take care of updating /optimizing your setup.