Spares are a good security blanket but I have been able to get out of a seriously damaged tire with a plug kit and fix a flat. I had a spare but the lug wrench from the dealership wouldn't fit the lug nuts. The hole was so big I eventually had to install 2 plugs and use fix a flat. I had to air it up a couple times but made it about 100 miles to the tire store the next morning just fine. But everyone should do what they're comfortable with. Not everyone has experience dealing with flats.