Hoover condensed tumble dryer not drying properly?

My dryer does not dry the washing properly. I have to have it on for over an hour for a couple of towels to dry and even then the washing ends up smelling damp. I had someone come and look at it and was advised that it was either the thermostat or the heating element. I replaced the thermostats and the problem still persisted. I was told not to bother trying to repair it if it was another problem as it would probably be just as much to repair as it would to buy a new dryer. Do you think I would be better off getting a new dryer?