Real-Debrid is a service that you pay for (approx £2.10 per month). when you are watching streams through addons like exodus and salts you are sharing those streams with millions of other users. This may (OR may not) cause you some issues and frustration with streams failing to play or buffering lots.
A real debrid subscription gives you access to much better, exclusive streams to eliminate these problems (though it will not compensate for poor internet connection so check that that is not your issue first)!
Not everybody feels that they need to add a real debrid subscription to their KODI setup. PErsonally i couldnt live without it!
Below is a video showing how to set it up...