Basically 3 trackers are enough. one on both feet, one on the hip. in some vr games like vrchat you can only use 6 point tracking anyway (headset, 2 controllers, 3 trackers).

So I use 3 trackers, two on my feet and one on my hips, and I have to say that's enough for full experience... anything more than that I think is luxury, unless of course you do strip in vrchat ;D.... but 3 is enough.