It totally depends on the keyword, how competitive it is, how much traffic it drives and how many links have been made for that page and that keyword.
Less competitive keywords stay for a longer period of time than competitive ones.
I hope it helps.
What Abhay said is true... If you have a competitive keyword and you stop optimizing for it, with link building etc once you reach top position you'll likely not be there for very long.
As long as you keep doing work on the keyword.
after doing On-page seo. Start Working on Off page like Article, blog posting and forums.
keep doing your seo smo on regular basis. the keyword will on top. and post blogs or articles.
Hello,
You should use SEO work for your website.In which On page SEO is an important part.
Until you keep on updating your website with SEO/SMO on regular basis..
Unless it start receiving competition or your website get banned by search engine.
Just want to know how long can keywords be content in top ranking.