Alright, I have some three month old strings on my guitar. They're fine and everything except for one thing, they're leaving some kind of gray residue on my fingers after I play a song. I was wondering if that means it's time to change strings. Should I? I forgot to add, not my hand on the fretboard.
yea man definitely time, get some Ernie ball strings to replace them, they sound great and stay in tune forever
no man take this edvice okay the best best best one are elixir a purple box get the light those are the best one

There is no "best string", you try out various brands to see what you prefer. I used to have Ernie Balls then switched to D'addario.

But yes, time to change them.
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generally it's a good idea to change your strings once every 4-6 weeks. if you start to gig and stuff like that you should do it every 2 weeks
tbh, i hate elixers. they may prolong string life alot, but imho, they sound like ****e, and feel as if they were drenched with oil. i say get a few packs of strings, of different companies. every time you change your strings, you'll be putting on new strings. compare the tone. and not the new tone i mean the old tone. how they sound after about a week or two of playing (although my friend is constantly playing, like, every second, and needs to replace strings every week). find the strings that you like the best.
a good starting point are daddarios, ghs (my fav), ernie ball, dunlop, dr, dean markly, and rotosound. these are generally the most widely used strings (i might be wrong here).
and dont let anybody tell you what strings to use. except elixers. some people might like them, but they are the only string that i cant stand the sound of.
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Peavey XXX 212 (back on the East Coast)

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Recommendations for changing your strings are like underwear. Some have holes in them and others have brown stains.

When I first started playing guitar, I used to change my strings every 2 or 3 months, because they would become dull looking and no longer sounded as good. I now use Elixir Nanoweb strings on all of my acoustics and Fender or D'Addarios on my electrics. I run the Elixirs about a year before changing them. I change the strings on my electrics every 6 to 9 months and they stay bright looking and sounding. The secret is wiping them down after you're done playing for the day and using some GHS Fast-Fret on them. Fast-Fret is mineral oil and it protects your strings and keeps them from corroding. GHS also claims that it helps you play faster, but that sounds like marketing hype to me. My son doesn't use it on his guitars and I end up changing his strings every month or two.

If you start gigging, you may want to change them a little more often than 6 to 9 months.

By the way, I'm not a guitar expert, but I play one on TV.
Alright, I'll try some different strings. I have used some Ernie Ball, not all only a few. But I keep trying new ones each time. Thanks for the advice.
If my strings seem to come out of tune really easily, does it mean they need to be changed? Thanks