This is not an oil consumption or an oil burning question, just wondering if there is any reason NOT to use an additive like Lucas or others just for prevention of engine wear or protection or whatever...
Oil additives are generally not a good idea for any reason. Motor oil is not just one ingredient. Modern oils contain detergents, anti-wear additives, friction modifiers, viscosity index improvers, antifoam additives, all sorts of stuff that has to be carefully balanced to get the right level of protection. It's complex and precise chemistry, and with newer oils it's more complex, precise, and balanced than ever before so they can meet stringent requirements for energy conservation, deposit prevention, etc., not to mention manufacturer requirements for starting speeds, heat ranges, engine tolerances, the list goes on and on. When you throw additives in the mix, it throws the whole balance completely out of whack, and you end up with a mix that might have the properties that the additive manufacturer promised, but the mix as a whole probably has some glaring deficiency that is nothing like what the engine manufacturer had in mind. You might even see some short-term benefit to using a particular additive, but in the longer term, I think it's going to cause more problems than it will solve. That's why manufacturers all recommend against using additives.
Do yourself, your car, and your pocketbook a favor. Use a high quality conventional oil (Havoline, Pennzoil, Motorcraft, etc.) in the viscosity that's recommended for the car (probably 10W-30), use a good filter (Wix, Purolator PureONE, AC-Delco, Mobil1, etc., but stay away from Fram), change it when the Oil Life Monitor says to change it, and don't use any additives. Put the money you save in your savings account, your retirement account, your kid's college fund, or donate it to the worthy charity of your choice.
That's my opinion anyway. I'm sure others will have plenty to say as well.