That raises another, and equally interesting question, about whether to carry a spare tire at all. Like you, I've not needed to change a spare in over 40 years. Yet I feel like if I don't carry one, I'd be tempting fate and get my comeuppance.
It has been discussed previously at either this forum or another I follow about whether to carry a spare. One point that was made is do we really want to be changing a heavy spare on a heavy vehicle? Possibly trying to change it on a roadside in danger of being hit by other fast moving vehicles.
I for one hope it never comes to that, but by having a spare, I'd only need roadside assistance to mount the spare tire. That is a service any place you call should provide.
I would also want to avoid a tow at all costs. Not only for the delay, but I've heard horror stories that they don't always send the proper tow truck for a vehicle the length, height, and weight of a class b. Interblog on this forum once posted her trials and tribulations on getting her rig towed in for service. It was a story not for the faint of heart.