Kowsar Hossain

If you want to make coupon code as a required field, this plugin will help.
During checkout when a customer will try to place an order without entering any coupon code, checkout process will be interrupted and customer will see an error notice.
You can configure the error notice text from “WooCommerce>Force Coupon” menu from admin panel.

Force Coupon for WooCommerce

A lightweight WooCommerce based plugin to force the customer to enter a coupon code during checkout

Abolfazl Sabagh

rng-refresh Plugin adds the meta box in edit post screen of the admin panel also you can add time period with template <code>Hour:Minutes:Seconds</code> of force refresh using it.
Main features in rng-ajaxlike include:
<ul>
<li>Very light and easy to use.</li>
<li>This plugin avoids from any conflict with other plugins.</li>
<li>has not any overhead.</li>
<li>Has a settings in order to determine post types that can have refresh meta box.</li>
</ul>
it is strongly was recommended that after the plugin is activated, go to the <code>Settings > Refresh Settings</code> and configure plugin.

rng-refresh

WordPress Plugin that refreshes the single template of public post types with a synchronism time period.

Force Coupon for WooCommerce vs rng-refresh