What are the recommendations for vit d deficiency screening?

High risk profile. Certain groups are at higher risk for osteoporosis and fractures: thin people, light skinned/northern european descent, smokers, history of prior fractures in self or family. But the number one risk factor is sedentary lifestyle, when there is little weight bearing activity. When astronauts return from a couple weeks of weightlessness, they are remarkably osteoporotic back on earth. Walk.Walk!
Varies among doctors. Because vitamin d deficiency is very common, and taking extra vit.D is safe & easy to do, some doctors only check vit.D levels in patients with intestinal malabsorption, kidney disease, bone pains & diseases, fractures, etc... Other doctors check levels on many patients who get little vit.D, such as people who don't eat dairy/fish/yolks, don't take vit.D 1000-2000u/day, don't go outdoors, etc...