"Rough" is probably not the best word to describe what I mean - but a new string doesn't seem to slide on the fret as well until it gets a bit of wear on it, unless it's a stainless fret, then it's slippery city from day 1.
For way to many years i just kept my strings on my guitars for as long as possible, because i thought that the dullness would translate to a darker tone - and i disliked the brightness of new strings.
Ironically old cruddy strings do bring out exactly the trebly shrillness that i so desperately tried to avoid, so the longer i kept the strings on the worse it sounded...
I am with the people who say that after an hour or two of playing new strings sound great for perhaps a week or two - and afte that it is a slow decline until the point where i don't enjoy the tones from my guitars anymore
I’m in the new string camp. I notice much more of an improvement in brightness with acoustic guitars. I notice less of a change on electrics. I always put new strings on the evening before or in the morning before I had a show - except that one time I didn’t - when a string snapped in the middle of a song.
I don’t play out regularly anymore, but when I do - new strings go on.
I am always removing and replacing pickups and hardware, so I go through a lotta strings. I usually loosen em up and just pull the loaded tailpiece aside, but you can't always do that. So I buy my Slinkies in 3-pack bunches.
I have 9 electric guitars in regular rotation and a tenth warming the bench. ALL of the strings are technically old. They get changed out when they are "done" though. I never change the plain strings unless they break (maybe once a year, just because). The guitars live in their cases due to space and storage limitations.
The D strings wear out the fastest. The A strings next.
I buy individual strings. 30 D strings, 20 A strings, 10 E strings at a time.
Once a year I buy 10 full sets. That gives me enough plain strings for the entire year and then some.
I play an average of one hour a day. It used to be more, but I do not currently have any additional time.
I don't change my strings as often as I did when I was gigging frequently...but no, I'm not a fan of old, dead strings. I play 90% of the time unplugged on electrics, and I like to be able to hear what I'm playing.