Hot take: power stretchers are worth the money, knee kickers are for closets only
I watched a guy at a job in Garland stretch a whole 40 yard living room with just a knee kicker and the wrinkles came back in 3 months. If you are still doing full rooms with a kicker in 2024, what is your plan when the customer calls back?
Did the wrinkles come back because of the kicker though, or because he didn't let the carpet sit first? I've seen guys stretch tight with a kicker and it holds fine, but only when the carpet was acclimated and they actually used a power stretcher to finish it off. Whole rooms with just a kicker is asking for trouble, but a kicker alone isn't always the reason it fails.