Yes, always bring a spare with you if you're travelling aboard by car. Prevention is always better than cure, who would know what will happen during your travelling because nobody can foresee the future!
You must always be prepared for the worst case scenario so yes you should always have a spare key with you. The inconvenience and time wasted if anything happened is just not worth the hassle.
I suggest whoever is travelling with you keeps the spare set just in case. You probably will never need it but anything is possible and the one trip you don't have it you will need it. That is how Murphy's law works when things go wrong, everything goes wrong.
Yes! my experience a few years ago while on vacation out of town I forgot to bring a spare key. I am very worried about losing the main key. now when I travel far what I remember is a spare key, don't forget. because worries will make us uncomfortable. From that now I always carry the spare key when I travel far.
Anytime I go on vacation or travel a long distance by car, I always take my spare key with me for safety reasons. The last experience taught me to always take my spare key 🔑 along. Anything could happen on your tour or travelling. So I decided to be absolutely careful with my keys.