SEO, as well all should know is a massive impact on our sites passive webviews. The higher our SEO the more monthly viewers we get without having to do anything other than build our SEO off the bat. However, what most people do not understand is that SEO is something that doesn't just stay. If you want to progress in SEO, rank higher on google OR maintain your current rank you need to be putting forth the effort monthly, without this the competition will slowly get ahead of you, some of the websites you have backlinks on will shut down, and you will slowly go back to being in the abyss of google's search engine. To prevent that all you have to do is simply continue to add backlinks, and build your SEO every month. Depending on the competition of your keyword it could be as low as 45 backlinks a month, or higher than 1,000 that's all dependent on what keyword you're going for.
Don't just sit there when you're happy your SEO is where you want it, or sit there and wait to see where your SEO you just paid for is. It takes 3 months for google to populate your SEO, which means by the time you realize your SEO position, or realize you've gone down in SEO it's 3 months TOO LATE! Don't get blind sided, and have to rebuild almost from scratch because of this, SEO is a very taxing thing, and it's something you MUST do monthly. If you want to save the time, there's ample amount of resources out there that will do SEO for you. One of them being Xyphien LLC one of the cheaper SEO companies out there, you can ensure you'll get the monthly back links and SEO building you need without breaking the bank.