Drupal Security Updates
The internet is in a constant state of change, so I suggest you keep up. Everyday there is new code pushed up, new modules, patches and security releases.
Think of your website like a new sports car. Every six months you're supposed to bring it in for an oil change or tune up. Your website is much the same, and every so often, you're going to need to update some modules or apply a security patch.
Now, much like an oil change, you could do this yourself. Or you could also bring it to a drupal shop, and have them do it while you read the morning newspaper and enjoy a cup of coffee.
You might ask yourself, how often do I need to schedule an update? is it every 6 months like an oil change or is it more frequent?
The answer to that depends on how many custom or contributed modules your drupal site has. The more modules you have, the more often you will need to check for updates.
In fact, there is a module in drupal that does this for you. It’s called Update Manager. You can configure it to check for updates daily or weekly and it will send you an email when updates are available. You can configure update manager at /admin/reports/updates/settings
Drupal has a method to their madness. They don't just randomly issue new releases. They actually have a schedule. For example, new releases have a wednesday window. What that means is that if there is a new release, it will most likely be posted on a wednesday.
Of course, this does not mean that a security release or bug fix will be issued on every wednesday, but the window exists so it can be pushed up.
Security releases are usually issued on the third wednesday of the month. New features and bug fixes go out on the first wednesday of the month. You can read more about this here: https://www.drupal.org/node/1173280
Contributed and Custom Modules
Unfortunately, contributed modules don’t follow a schedule and are pushed up as they become available. Usually, if everything's working on your site, you don't need to update it unless there is a security fix. However, you also run the risk of falling behind and modules can become unmaintained. It's always a good idea to keep a pulse on what's available.
I would suggest running updates on a monthly basis to stay current. Like a car, the longer you wait to get it serviced, the longer it's going to be in the shop. And we all know what that means...
If you're wondering if your site’s falling behind, have a look at our Drupal Site Audit service. Security updates are just one of the things we look at in our 64 point inspection.