Following a recent incident, I now carry a wheel wrench extender bar.
Routinely, I carry sleeping bag, water, spare dog food, wellies, set of waterproofs, loo roll, spare bulbs, rope, foot pump, torch, radweld, WD40, spare specs, spare valve caps, and a spare wheel nut.
About 6 months ago on the way home from Liverpool, I heard a strange knocking sound coming from a front wheel. I pulled over and investigated but could see nothing untoward. It got worse and worse and the steering became very loose. I managed to get to a friend's house and discovered that a wheel nut was missing and 2 of the remaining 3 nuts were very loose, the wheel was only held on by 1 nut. I was in a total state of shock - in 25 years of driving this is the first time this had ever happened. I can't believe how lucky I was that day. Another couple of miles and I would have lost the wheel. I tried various different places to get a new wheel nut - petrol stations, Halfords, garages and couldn't get one and had to go to Peugeot, so I bought a spare aswell as a replacement. I'll probably never need the spare but having come so close to disaster once, I wouldn't risk it again.
And I have't got any thing against Liverpudlians (my dad's family lives in Liverpool) but it's odd that it happened after being parked up at Crosby Beach for a couple of hours... next time I go to Liverpool, I'll go on the train!