I've never found the need to do it before flowering. I usually do it right after the stretch(2.5 weeks into flowering). Between pot and root ball, I stake in 4 spots. Pull a branch to each stake, twist tie them off. Then use twist tie to secure branches that are going to need it. Don't just wrap the plant with twist tie, it bunches it up. I then lollypop/ prune lower stuff as necessary.
Right after doin all that, I fire up a doobie and remind myself that i won't have to do another dam thing to those plants(hopefully), except feed/ water them until chop time..Gone are the days of walking into the room to find plants have fallen over. What a pain in the ass! the stakes can help shape your plant and therefore your garden to.