I was looking at quite an amusing thread earlier where everybody listed the contents of their badminton bags (and I think some of you carry WAY too much stuff!) and I noticed quite a few people carry badminton strings. Is this to repair broken strings by hand? I wouldn't have thought it would be worth it for most players because the performance/tension will drop if you just try to replace a couple of strings in the middle.
I really don't think it is possible to repair strings by hand (without tools or machines) People have strings in their bags because if strings break, they can just send the racket with strings to their stringers conveniently.
I usually brought several samples with me (BG65, BG65Ti, Winex Ti80) to show ppl the chart on the bag, and to help them make decision about which string they prefer to be on their rackets.