We started with CPT twice a day when he was week old as a preventative. When he's sick we go up to four times a day. We received the vest 5 months ago (CPT was becoming a struggle)and LOVE it! No more aching arms/wrists, no more battles. We started at 15 minutes 2x a day and are up to 25 minutes 2x day with the ultimate goal of 30 minutes. I would definitely question the CF center about getting a vest.