Takes too long for towels, etc to dry; have to dry more than once. Normal clothes appears to dry OK?
When is the last time you’ve had your dryer vent system cleaned? It sounds as if The vent system is not allowing the water vapor (steam) to exit the dryer as fast as it should. Cleaning the vent system includes not only the duct work to the outside of your home but also the transition hose (slinky hose between dryer and wall) as well as the interior of the dryer vent from the lint filter, to before and after the fan, to the discharge on the back of the machine!
A dryer can only function if when the clothes are heated to a point where the moisture is removed from the material and exhausted through the vent system. Most exhaust vents should move 100 to 125 cubic feet of air per minute. If it is clogged or partially occluded, the moisture stays in the drum hence the clothes won’t dry.