have to change light bulbs

My husband already checks the light problem in the study room. He said is the light bulbs problem. He has to change three light bulbs at the same time! He complaint to me do not know what happen to those light bulbs, seem have so many problem lately. Those light bulbs do not cheap at all. Well, I am surely do not know the real reason, maybe many manufacturer is cutting cost now and use some cheap materials. If not how come products quality become worst even the price still selling expensive?