It's hard to run a household efficiently when your appliances are not working properly. If your dryer is not tumbling, there are a number of things that need to be considered. Consult a professional repair service to locate and repair the problem.
If the door switch, located inside the main door frame, is defective, the door will not close properly. The dryer cannot work at all if the door cannot close. A technician can determine if this is the problem and replace the door switch.
Burnt Out Motor
The motor may be burnt out in your dryer. Remove the belt and check for anything that might be obstructing the housing where the blower fan is located-- if that is clear, then try to rotate the motor. If the motor is stiff, it is probably burnt out and needs to be replaced.
There is a drive belt that turns the drum. If the belt is worn or has broken, it will need to be replaced. At the same time, check the idler pulley because often that will need to be replaced at the same time as the drive belt.