Maintenance mode comes in handy when the site is not yet fully ready or you want to restrict access to the site while making some changes.
Additionally on the maintenance page you can add a countdown timer, subscription form (list of subscribers can be exported in csv format), display links to social networks, add a pop-up feedback form and Google Analytics identifier to track the actions of site visitors.
Site developers sooner or later face the need to enable maintenance mode. When a site visitor tries to go to a page of a website under maintenance, he will see information that preventive work is being carried out. This is the service mode. The site is completely closed from visitors and is available only for correcting technical issues. Thus, the programmer or layout designer can safely change the content of the page, fully making sure that no one can interfere with this process.
Usually inventory management in the retail industry is chaotic. The business starts with one or two stores, a few years later the network has dozens of stores, branches, distribution warehouses, etc.