I don't use shampoo on my dogs most of the time. They smell like dogs but not bad, or I've gone "nose blind" to their perfume!
In the absence of allergies or other skin conditions or a recent skunking or rolling in dead, stinking carcasses, labs shouldn't require shampoo baths often. It can wash out the natural oils and dry their fur and skin, which can become itchy, making the owner think they need
more baths, making them drier and itchier. If Murphy has no reason to be bathed other than he smells like a dog, which he is, you may wish to just try more frequent brushing and wiping him down with a wet wash cloth, even one doused in a little Listerine diluted with water by 50%, to freshen him up.
I usually just hose mine off with plain water, outside in a plastic baby pool whenever possible. That generally makes both dogs run around like wild, crazed animals, and Chase often heads straight for the dry, loose dirt under the pine trees to roll around and requires a second hosing. During the winter or when it's too cold outside, they mostly don't get bathed but if I had to, I'd take them to a local self-service dog washing place.
I use a Kong Zoom Groom and just make kind of circular movements with it when washing them to help loosen the dead hair. I dry them as thoroughly as possible with towels. Mine don't like the blow dryer particularly, but I've used that sometimes. Chase's fur is super dense and takes forever to dry. Chase loves, loves, loves water and baths and will lie in the baby pool for hours getting massaged. Lark gets in and out but doesn't lie in the pool under any circumstances.