I'd rather have them and not need them, then need them and not have them.
My little black gelding has never needed them. He's soft and responsive, listens well to voice commands as well as light leg cues. I still wear spurs when I ride him, but (again) only as a "just in case."
I've known other horses that are fine 99% of the time without spurs - but it's good to have them during that 1%.
There are people who over-use spurs, just as there are people who over-use crops/bats and bits.
"Parelli horsemanship is just like painting by the numbers. You need absolutely no skill. You just put this color here and this color there, and when you're done, you have ... a mess no one wants." mp