You will probably get a few different answers here as well. If you got your puppy from a good breeder of labs, my first suggestion would be to ask him or her when to make the switch. They should know what their labs do best eating. Some breeders even skip the puppy food and go to an All Life Stages formula.
I got my labs from 2 different breeders, both of whom said to switch to adult food around 4 months. Others have said to make the switch after their baby teeth come out and are replaced by their adult teeth, still others have said they were told to keep their dogs on puppy food for the first year. Assuming the breeders I worked with knew what worked best for their lines, I switched mine to adult food by 5 months of age. At about 4 months, my younger pup was having some GI issues and my vet had suggested a change of food. When I said I was having trouble finding a fish-based puppy food, he said she no longer needed to be on puppy food anyway. I delayed changing that pup's food to adult until the GI problems were done.
Adult foods do not need to control the calcium and phosphorus level as closely as puppy food does. I've read that labs do best with a lower calcium level and calcium to phosphorus ratio (which should be in the 1:1 to 1.3:1 range) until their bones are mostly done growing. That might be the ones who say to switch at 1 year of age. Our breeders were feeding ProPlan, which adheres to those ranges in both puppy and adult formulas but this is not to recommend ProPlan or any other specific brand. Just saying there are adult foods that meet these recommendations.