It all depends on how you treat your tires, especially how you drive and maintain the correct pressure. Lower pressures allow the sidewalls to flex more and weaken them.
I have a 2009 Chevy Equinox, and only once I need to stop and replace the bad tire with the spare because I ran near a concrete border that cut the sidewall. But other than that, no leaks or flats on normal roads. My previous car was a 1995 Buick Regal, and in 21 years it only had one flat. I used a "Fix-a-Flat" inflator can to fill it up and the next day had the tire puncture repaired. I NEVER used the spare in the trunk!
The newer cars that have the special inflator work on that plan: pump air if the pressure is low, and use a sealer to fill and reinflate from a puncture. So they never need the spare. Having the inflator kit is much more useful, and weighs less, than a spare and a jack. And if you can't get an inflator kit, get a inflator can and store it in the rear (I keep one in my Equinox).