I agree theres no way of carrying a spare under the van other than a deflated spacesaver, maybe, if you dont have belly pans.
Like most things, theres no single answer.
I have just had a think and can recall having had a total of eight punctures over the last xxx years :lol:
Three were minor and could have been fixed with tyre weld, though two of them were so slow that just pumping them up and driving on to a tyre place was possible.
Two others were big holes, one caused by a really huge screw, at 11pm at night, in the rain (of course) and in the middle of nowhere in France. The other was caused by running over a stone at speed which bizarrely knocked out an almost circular hole in the middle of the tread that was about 2cm in diameter.
Two more were sidewall damage, one caused by mechanical thrombosis - hitting a kerb - and another by a chunk of metal. The final one was a motorway blow out which blew a hole in the sidewall big enough to put your fist through.
These were all on different vehicles by the way - just in case you were wondering :lol:
Anyway, the thing is, had I only had tyre weld I would have been ok on 3 out of eight times (which is not acceptable to me). I like to be as independent as possible and carry spare parts etc in the bus when we go away, especially since we like to go off the beaten track.
So I guess what I am saying is, its a personal choice which has to be based on how much you want to depend on others, tempered by where you go.