It seems that some webmasters add a noindex command to the robots.txt file of their website when they go on vacation. Google’s John Mueller has said on Google+ that you should not do that:
“PSA [public service announcement]: If you go on vacation, you can leave the website up, and you don’t need to noindex it. ”
Of course, it is a bad idea to add a noindex command to your website if you want to get high rankings. Use the website audit tool in SEOprofiler to make sure that search engines can index all pages on your website correctly: