Like most questions on this site, it depends. Chronic venous insufficiency, of which varicose veins are one consequence, is the most common disease in North America. In fact, if you add up diseases 2-5, they don't exceed CVI. It affects one in eight Americans, with over half being symptomatic.
Symptoms occur often and can range from pain, fatigue in the legs, bursting feelings, itchiness, burning and swelling all the way up to ulceration and skin breakdown.
Seeing a vascular specialist allows one entry into the system. A duplex ultrasound should be performed (a noninvasive pain-free test) that evalutes the patient's venous valves. Most PPO's allow treatment for symptomatic legs that have 500 milliseconds of reflux. That means the blood is flowing the wrong way in the veins for over half a second (away from the heart).
If this is present, insurance will often cover an ablation procudeure to rid one of reflux and removal of the varicose veins (often called microphlebectomy).
If reflux is not present (which it almost always is with large painful veins) the treatment may be considered cosmetic and then it's on the patient to cover the cost of laser/sclerotherapy or surgery. Hope this helps.