I have had customers who rang with a puncture late at night , only to find they had those stupid bottles of tyre repairer and an ineffective electric pump, none of which if they had worked would have solved the massive split in sidewall caused by driving over a rock!!!I've just been to look and found a second hand wheel with tyre on ebay for £70.
I no longer carry a spare, i've not had a flat for over 15 years now, and i'm not expecting one in the next 15...instead i carry a tyre inflator, if that fails i could drive off a motorway and then replace the wheel later.
Whereas a effective spare wheel would have got them mobile again instead of vehicle being pushed into someones drive and waiting until Monday for tyre shop to open!