I've always been more than dubious about the puncture repair gunge which you can use and is increasingly supplied with new cars. In the past, I've always invested in a proper spare wheel or at least a 'space saver' one.
However, my views are based on discussions I had with someone in the tyre business some time back (decades) who said he wouldn't repair a tyre which had been 'repaired' with gunge as it was all but impossible to ensure the gunge could be removed so a proper repair could be made. (I appreciate the gunge is no more than a temporary repair).
However, with the passage of time, have things changed? Do people find that they must replace a tyre which they have used 'gunge' on (assuming the damage would normally be repairable).
My question is more than academic- I collect a new car at the weekend and not only does it lack a spare wheel, there isn't space for one (the space is occupied by electric motors to drive the rear wheels).