theres no absolutes in beer brewing. I leave mine carbing in keg at serving preasure for one week to a week and a half, then i let it sit for another week or so and then i drink. its going to age over time anyway so i can experience the beer over the course of weeks or many months.
as for secondary. if my beer has a poorly floculant yeast, i will secondary to clear and then keg, or leave in primary for double or tripple the time required to clear.