re: sales tax on labor, yay or nay?

In my mind, if the labor is the end product that you're selling, then that should be taxable by a sales tax. In your particular line of work, your labor is your main product (though you do sell parts, which are definitely taxable), but the labor should also be taxable because your labor is the main part of your business. However, if you're building a product like a house or a car in a factory, then that labor should not be taxable under a sales tax because the labor itself is simply an input into producing the good that is taxable under a sales tax.

Of course, my thoughts mean nothing put up against the law, and the state of Louisiana may disagree (it does love to tax EVERYTHING), but my personal thoughts on what's subject to a sales tax simply comes down to "that which is sold to an end consumer on the open market is subject to a sales tax". The labor of the supply chain should not be subject to sales taxes, only the final product/service.