SEO stands for search engine optimization. It refers to techniques that help your website become more visible in organic search results for the people who are looking for your brand, product, or service via search engines like Google, Bing, and Yahoo
Once off SEO will help, but at least three sessions are recommended to at least get the momentum going with regard to the number of keywords in the top 30 positions. We normally suggest 6 months as this allows time for site to compete with the other sites.
You can choose to do SEO as and when you have the budget or when you think it is necessary. Once every two months, etc.
Organic results are the results that appear in search engines, for free, based on an algorithm. Paid — or inorganic — search results appear at the top or side of a page. These are the links that advertisers pay to appear on different search engines.
meta description is the text that appears below your page in a search engine result that explains what the page is all about.
Meta descriptions still matter, just not in the same way they used to. They used to be a place to optimize for keywords so crawlers would know more about your page contents; now, it’s more important you write something compelling that makes readers want to click so you can improve conversion rates from SERP results to your website.
Unfortunately, I can’t tell you an exact number that is the “right” number of keywords on a page, mostly because that’s the wrong way to think about keyword optimization.
There’s no keyword density you should be aiming for — in fact, using a keyword too many times can result in penalization due to “keyword stuffing.” Just keep the reader in mind, and only use keywords when you need to. You’ll find enough natural opportunities to include keywords that you won’t even have to worry about reaching an arbitrary number.