A good recumbent bike should feel smooth and run quiet. Over time some internal components can wear out that cause the resistance to slip or the ride to feel bumpy. If thats the case with your bike, chances are good its going to need a new clutch pulley.
Foot levelers break easily if the bike is moved around or if it wasn’t leveled properly.
Pedals wear out fruqently and you can tell by the vibration in your feet and also the squeaky sound it will sometimes make.