I thought I saw this question before today...I'll check..
If you take care in putting on wax correctly, meaning that you are putting it on clean paint and thoroughly stretching your wax by buffing it well, then you can put on as many coats of wax as you like.
Contrary to a lot of beliefs, and depending on the quality of wax that you use, there are visible differences in a paint's resolution that can be obtained by putting on a good amount of wax coatings. A very good wax with a nice build up of let's say....my favorite range, between 8-12 coats of pure wax, can produce a deeper resolution than between one and three coats of a wax. This is based on my observations though, so you will, of course, have to do some comparisons for yourself.
On the downside, your wax buildup will have to be removed at a point, because continued applications without cleaning the paint, let us say again, over a year without cleaning, may start to produce a resolution that contains dullness or cloudiness. The dullness a combination of oxidation of the paint and trapped contaminants that has to be cleaned from your paint.
You should give yourself a good buildup IMO between 6 to 9 months and then re-clean and start over. If you live in a temperate climate where you see moderate to harsh winters, then build up your coatings during the warm season, ride them through winter, and re-clean at the start of spring. This routine works well for me.
