I usually lunge my horse without tack because the ring I put him in to lunge is pretty dirty so I don't want my tack getting dirty as well. He sometimes throws a few bucks in their as well so I'd prefer if nothing happened to my tack in the process and it doesn't get scratched. He only time I'd really lunge with tack on is before a show because u don't have a lot of time to get ready and if your horse requires it.
Exactly what Abby said! If I’m lunging I usually don’t end up riding so I don’t use tack. I feel it allows them to move freely and more comfortably too. Maybe that’s not true ahaha but it seems like it’s true for my horse.