Personal preference. I do one full detail in the spring and than use PB's Black Hole and a sealant for the remainder of the season. (my car is 8 years old with SS paint)
On my daily driver I use a glaze (Meg's #7 or RMG) two to three times a year when I do a full detail. On my MR2 (garage queen) I apply a glaze an hour or two before the show as a topper and reseal after the show.
