Do I need a Plugin for WordPress SEO?
There are hundreds of SEO Plugins available for WordPress. Many people use one or many Plugins for SEO on their WordPress Websites. The question however is if you really need a SEO Plugin in the first place.
WordPress has an excellent architecture that makes it very simple to Search Engine ‘bots to index and understand the content within a WordPress Website.
If the content itself and the content structure of the website are of high quality and well thought out then there will be little benefit of additional SEO plugins.
Many Websites however do benefit from the additional SEO benefits such as sitemap.xml auto-generation that SEO Plugins provide. A word of advice regarding SEO Plugins; be very careful and do your research before installing and using an SEO Plugin as some can harm your SEO.
How will caching help SEO
Yes, your WordPress website will load faster if caching is used. Page load speed is a Google ranking factor therefore caching will likely help your SEO as your website will load quicker for visitors.
Caching is basically a snapshot of your webpage, or items of your webpage, being stored on the visitors computer or on the server ready for quick delivery.
There are various means of enabling caching on WordPress. The simplest of the ways of enabling caching is to use a service such as CloudFlare or a plugin such as W3 Total Cache.