The packet I got says to administer it on days 1, 3, 5, & 7 of the first week, then just once a week after that for maintenance.
I looked at the probiotic page, http://www.guinealynx.info/probiotics.html, but didn't see any reference to frequency and didn't find much about that specifically when searching the forums. Sorry if I missed something there, I went through a few pages of search results.
If the piggy is healthy once a week "maintenance" dose seems adequate. But does the guinea pig community recommend more frequent use if/when the guinea pig is on antibiotics?