It's human to avoid big changes, especially when it comes to adjustments that affect our work. So it's not surprising that while Salesforce introduced the Lightning UI in 2014, not every organization has adopted it yet. Some wanted to wait until the bugs worked out and more functionality was added. Others put it off, knowing it'd be a lot of work to support. However, that won't be an option forever.
Starting in the Spring '19 release, Salesforce announced that it would no longer add functionality to Classic. Now with the Winter '20 release, Salesforce will be rolling out Lightning for all organizations, starting in January 2020 (delayed from the original October 2019 date). Salesforce has yet to announce an end date for Classic, but these steps show it's possibly on the horizon.
If you haven't already, now is the perfect time to start transitioning your company over to Lightning. Even if Salesforce never discontinues Classic, it's still beneficial to your users to be on the same Lightning UI where Salesforce continues to add new features. Plus, it will simplify processes and requests on your end as you won't have to test everything twice over. Here are some steps Admins can take to gain user adoption in Lightning:
Once users start making the switch, you can always track the progress of user adoption through the Lightning Usage App. To open it, click the Settings icon in the navigation bar, type "Usage" in the search box, then click Lightning Usage. It'll even show the pages or reasons why people switch back to Classic. It might enlighten new ways to configure Lightning to better serve your company.
The combination of training and personalizing their user experience inside of Salesforce will make employees more willing to take full advantage of the technology they are already paying for. Training in Trailhead or in person will answer any questions they have right away, making them more comfortable with the new design. Cleaning up the org and re-configuring certain processes to be smoother will also encourage user adoption, as it will make their jobs easier.
It won't be an overnight process, but your future self and your peers will thank you for starting the transition now. That way, if Salesforce sets a date to turn off support for Classic, your org will have nothing to worry about.
Along the way, if you find improvements that need to be made, we specialize in apps for Admins. Our Helper Suite can assist with rollups, lookups, storage, and team organizational needs.