The default timeout of
sudo is 15 minutes; that is,
sudo will remember your password for 15 minutes by default.
You can modify this default timeout by adding a string in the file
/etc/sudoers. However, you don't modify the file directly, but instead you use the command
sudo visudo in a terminal. This will open up the (actually, a temporary) file for us to edit, using your preferred editor.
Note: if you are using
visudo for the first time, you should be asked which editor you would like to use, so choose your editor. There's no "better" editor, but I prefer
nano. If you've already used
visudo and chose an editor before, but you want to use another editor for the time being, you can do
sudo EDITOR=vi visudo to use
vi, or change it to
nano to use
nano. If you want to permanently change your preferred editor, do
sudo update-alternatives --config editor.
Look for this line:
timestamp_timeout=X (with a comma) at the end of it, where X is the time you want to set in minutes.
So your line should look like this, as an example:
If you specify 0, you will always be asked the password. If you specify a negative value, the timeout will never expire.
Once done, save and exit.