It isn’t very necessary to update for each update. (If you don’t use WooCommerce, It is not very important to upgrade v2.3.1 – the latest version for now).
The normal update will not hurt the existed content(posts/pages/settings). I still suggest you make a backup before any update, there is a backup tool on host cPanle normally. Or use a backup plugin like https://wordpress.org/plugins/duplicator/
But please notice there will be a big update version 3 in the future(1-2weeks). Please be careful to update. It WILL hurt the existed content. Please always read update-log page or theme page(LOG) if you want to do update.