Should I mix up anchor text
 

I have read on some forums that it is a good idea to mix up my anchor text from time to time, in an effort to avoid any Penguin triggers. Can anyone confirm this?

Yes, you can mix them up, use similar one. For example, you want to SEO this keyword: Best laptop 2013, you can mix it up randomly like this: Best laptop, Laptop 2013, Cool laptop, etc. Don't stick with just 1 anchor text.

Yes you need to use mix keywords to get natural ranking in Google. If you are going to work on same keywords more and more then you will loose your website ranking after Google penguin update.

Its a better approach with mixing up your keywords but changing it time to time won"t be a good idea.

Anchor Text is highlighted in website content helps to better keyword rank ratings.