More important than size is comfort. My dogs (also labs)kennels vary in size from 6x6x6 to 12x6x6 and I could go with 24x6x6 if I just wanted one large kennel. The 6x6 is big enough for our little girl (45#) but our male is much bigger (90#) and the 12x6 is much better for him. They need afternoon shade in the summer but love the early morning sun, they need clean fresh cool water in the summer and a dog house to get out of the rain/snow in the winter. My kennels are covered so out of the weather is a given but the dog house is there for the cold nights. All day shade areas for the water to keep cool, concrete floors and solid wire sides to keep my dogs safe from themselves while we are away. My yard is fenced but the dogs are always locked up when we are not home. The last thing I want is one of the kids friends coming over and letting the dog out when they open the driveway gate so dogs are always kenneled when we are gone.
I would think 6x10 would be good for any lab, just make sure it is stout and built for more dog than you will ever put in it.
