A Helper can be used to retrieve logic which can be used more then once. For example the module function isEnabled.
Use the snippet in the Magento 2 module creator.
Mage2Gen is an easy to use open source module generator for Magento 2. With the extensive interface the user can easily generate base code for a Magento 2 module.
The following parts can be generated by Mage2Gen: controllers, models, blocks, template files, plugins (the new rewrites), observer, console scripts and product attributes. Even more will be added in future updates.
Once logged in, you can save all of the generated modules. This enables you to go back to a module and generate a part that you possibly forgot when you initially created the module.
When the module is complete, you can download it as a zipfile or immediately install it with the provided wget shell command!