How quickly is the internet browsing info...?

How quickly is the internet browsing information deleted from your WiFi network router if you used a device that uses WiFi such as an iPad(I already cleared my history and cookies & data in the ipad's settings)and how do I delete it from the network itself and/or my home computer? Once I delete it can I ever get it back? How do i delete EVERYTHING whereas no internet browsing history remains? Is there an easy and efficient way of doing this? Can you delete EVERYTHING so there is not a single solitary trace of internet browsing history? Please answer all of these questions. Please get back to me on this.