I, personally... prefer to record and play live on strings that have been broken in well past the stage of still being called "new".
1. Because that's when the strings get the best tone...
2. They become easier to play after they've been broken in. They tend to lose that slipperyness.
3. I like worn in strings because they get a better warm tone generally... Newer strings will sound bright until they've approached the modulus of elasticity (engineering mode... sorry)... Strings stretch continuously as they're always under tension... That's why they go out of tune a lot when they're new... Because the metal has never been under tension and it's stretching at a high rate... Once the strings approach the modulu of elasticity... or the apex or their elasticity... the metal slowly stops stretching... Until eventually the apex/modulus of elasticity is reached and the string snaps... usually at the bridge or the nut.
Those are the main reason I like to break my strings in. Sometimes I'll leave a set on my backup guitars for 8 months at a time since I don't use it all the time... my main guitars usually get a string change every few shows or every month if I don't play any shows or record... it usually take a good ten hours of play to really work a set of strings into shape for me... I use Zakk Wylde GHS Boomers .10-.62 or whatever the E string is... A heavy set... so naturally they take longer than a light set of strings would to break in.
Remember to always stretch your strings when you install them... this will speed the process of breaking them in and will help them stay in tune longer...
Also... some people that only have one guitar or only play one guitar have a hard time telling when their strings go sour because the process is so slow that they don't notice it as it's happening... But they'll notice it right away when they play a guitar that has fresh strings... or when they jam with someone else who CAN hear the sour strings... It's always a good idea to keep on a string changing schedule regardless whether you play shows or record... Just so you can ensure that your ears and strings are playing a joke on you by making you think everything sounds like it should.
