I make it easy by carrying not only a spare inner tube but also a spare tyre (I use folding tyres which weigh about 440g and fold up quite neatly in the pannier.. So, I remove the tyre and inner tube and replace both then deal with the puncture in the warm, dry and calm at home (or that could be the B&B or campsite if you’re touring). I feel it’s worth it to carry these spares even on day rides.
As destroying a tyre is a rare event in my experience I don't generally bother carrying a spare.
In about 48 years of cycling and about 266,000 kms I have only had 3 tyre failures that were bad enough to need immediate replacing or bodging a repair to limp to somewhere I could buy a new one. I have had the same number of frame/fork failures, and nobody would think of carrying spares for these.
The first, in the old narrow 26" size, could have been bodged with the tyre "boot" in my toolkit if necessary, but I was less than a mile from a bike shop when it failed, so I didn't bother and just bought a new one.
The second was a very cheap and inferior 27" tyre, and I got a replacement for that in less than an hour from another cyclist. Lesson learnt - get decent tyres.
And the third was a lightweight 16" tyre on my Brompton. But as I knew these were fragile and in a size that was hard to find I did have a spare with me that time. And with a folding bike I also had the option of finishing the trip by public transport.
I reckon that the reliability of good touring tyres has improved in recent decades. The first two failures were in the 1970's, and I haven't had a catastrophic tyre failure on a large-wheel bike since then.
I would still definitely take a spare if going somewhere really remote, but in most of Europe I reckon it is easy enough to find a 26" tyre.
And before I go on a tour if I think a tyre is a bit too worn I replace it with a new one, and generally put the part worn tyre on a utility bike to finish it off on local rides.