seeing as how intensity and volume are directly related to that answer, only having frequency is near worthless info.
in other words, i have done it where i hit a muscle once every 10 days and my intensity was extremely high. i have done others were the volume a week is the same, no matter whether i hit a muscle once a week or 3 times a week.
in other words you can gain on hitting a muscle every day, every other day, every 3rd day, 4th, 5th, ad nauseam. it will work as long as volume and intensity are at the level to match your current work and recovery capacities.