kepp having to replace 2-3 times a year

Why do the headlights keep going out. They cost now $94 each plus tax. When one goes out the other one goes out approximately 3weeks later. None of the parts stores can explain why and refused to replace the. I have to have a professional replaces the bulb at an additional cost of $70 for labor because of the difficulty of replacing it. Could there be a electrical problem? Does these headlights have a fused connection? When I ask questions I get this response: This is a common problem with Volvo. This response is not good enough. This problem is very costly, especially for someone on a fixed budget. Is there an Volvo car dealer out here somewhere that will take the time to check whatever needs to be checked at no charge? Someone help me please. Thank you, Ms. Bea