The following can make a flourescent fixture hard to start. If the temperature is below 50oF. If the lamps are old. If the fixture is turned on and off constantly and you are using a rapid start ballast. If the voltage has dropped. If the ballast is weak. Replace the ballast with a commercial grade instant start ballast such as Advance, MagnetTek or Osram/Sylvania and Sylvania, Philips or GE u tubes and it should work fine for a minimum of 5 years.