I do if I dry hop or need extended bulk aging to get a higher gravity beer off the yeast for months on end. Plenty of different opinions out there but in past attempts to keg my beer after dry hopping in the primary has lead to a lot of hop matter that clogged keg posts. Reason being, the pellet hops settled on top of a large yeast bed and got sucked up in the syphon. Rarely do i get much hop matter when i syphon from a secondary. Though i exclusively use pellet hops only. it works for me and I've never had any oxidation problems.