Joel sounds like my boys -- He doesn't work for free.
For the most part, it is okay. Ideally dogs should know to follow commands without always receiving a treat. I'm guessing a lot of pets need a food incentive often.
My boys will always do a sit no matter what, but they are less reliable on all other tricks unless I have a treat for them. Teddy will come when I call him, but Max usually needs more encouragement like food or his harness to go walking.
In an emergency situation, like if the dog gets out or loose, it is good for the dog to know how to respond without a treat incentive.