Over the years I have noticed that often there is a recommendation for two coats of primer. If the purpose of a primer is to create a bonding layer so that the paint will adhere properly than why two unless the previous color shows too much? I’m changing a brown colored lacquer finished vanity to a white color. After a coat of BIN I intend to apply two coats of the final color. (All sprayed) The primer has hidden the brown completely so would there be any benefit to a 2nd coat of primer?