How often to apply wax,to cabinet?

Wax, once applied, doesn't go anywhere unless removed by friction or abrasion. No need to reapply as far as the protective aspects go unless you're rubbing it off somehow. I would not agree that wax is the ideal panacea for wood care. Veneers can dry out and delaminate. I have been of the opinion that keeping room humidity levels high enough is more important than any waxes or oils. If wood veneer becomes dry, an oil purpose made for remoisturing wood is a good option.

Does any wax or oil actually penetrate for moisturizing into wood that has been laquered or varnished?

When building a cabinet (I'm a woodworker) the adage goes: "Once a day for a week. Then, once a week for a month. Then, once a month for a year."

What kind of confuses me is wax over laquer. With most laquer finishes - think of piano black - applying wax over laquer would only dull the finish. Assuming that your speaker cabs look better for having done the wax job previously, I'd say go ahead and do it again if you think it needs it.

Wood moves. Wood or wood veneers can dry out. The point of the laquer finish and wax is to radically slow down the process so that it takes decades instead of months to dry out (or sponge up.)

To answer your question more directly: If it's been a year, you would likely want to do it again soon.

/Rob

PS: Feel free to contact me offline with any other wood questions you might have.

Wax is done, once wax is done... The only reason a car needs re-treatment is of course going thru the sun, rain, cold, hot, dirt off the road etc.... It will break down and become necessary to re apply... Speakers, well unless you travel with them playing in the back of your pickup running around, they will be fine once shined up in your living room... Of course fingerprints or something could cause you to do a quick touchup.

Gammajo, any finish that will protect wood from water damage isn't going allow moisturizing oil to get into the finish either. Naturally oily woods like teak that have an oil finish do benefit from occasional moisturizing with oil I think. But most hardwoods don't have much, if any, natural oils that need replacing. After thinking about this, I imagine pretty much all speakers are manufactured in plants that use a catalyzed urethane or acrylic lacquer finish. If this is the case, the wood is sealed and waxes are only going to protect against abrasion and help to keep dust from adhering to the finish. Again, the best protection for good wood is to avoid large humidity fluctuations and air that's too dry.