How to make a terminal remember sudo passowrd for ever

when you type sudo command for the first time in a terminal it will ask you the sudo password.
This password will be remembered by that terminal for 15 minutes by default.

If you want that terminal to remember your password for ever during its life time follow these steps.
1. Type at terminal

sudo visudo

2. Edit as shown below

   Change

    Defaults env_reset

   to

    Defaults env_reset,timestamp_timeout=-1