Yeah but you’ve been warming up since the 70s. 
But I admit I only warm up before a practice session. If I just fancy banging out a few songs, or just having a go at something that might be a good learner, I’ll just pick up and start playing, Like you say playing is playing, practice is practice.
That’s is why shoulder hurts 
Even pros practice the songs they ve known for years especially before a gig
Actually no they don’t. They practice preforming the sets they are going to play at the gigs they’re going to do.
I know you’re going to say Steve Vai and Tommy Emmamual practice for 8 hours a day but they don’t practice songs they practice to keep their chops up. When you play at that level you need practicing to stay loose so you can play at that level.
There is an old saying amateurs practice until they get it right, pros practice until they can’t get it wrong.
On a recent interview with Beato, Sach says he warms up for an hour before a show.
Getting the hands, mind all up to speed and in the groove takes a bit of time
no … i wasnt going to say that
I know whats been bothering me with your sentence
Im a pro artist in life , I’ve been a cartoonist for 15 years ( doesnt make me any younger 
)
From my experience in art i can tell you that there is never ever a moment when " you know your stuff its done "
Every line you draw , every note you play IS practice , always , in all circumstances , all your life !
Look at Calvin and Hobbes by bill Waterson , look at the characters in the first book and the last , they are completely different , because every book he drew made him better , and the lines evolved
thats something you can t control
A famous comic artist who said once : Every time i start a new comic book Im a beginner again , just because he gained experience and evolved while drawing the precedent book
and believe me the guy is crazy famous in Europe
he was right and its the same with music
So , no there is no practice VS play
playing IS practice , its the same
and it teaches humility
Then you don’t know how to play. I’ve been playing for almost 50 years, some of that professionally.
When you go out on stage the last thing you are doing is practicing. You go out on stage to put on a show and play to the audience, the last thing you want to do is practice. Evolving a skill comes with repetition, you just get better and better the more you do it.
Besides this thread was about “How long does it take warming up?” not whether strumming a song is practicing.
Practice is learning and refining specific techniques etc to improve your playing skills by working on your weakness focusing on specific things whether its chords, scales, pick control, hybrid picking etc. Playing is fun and develops your performance skills but it doesn’t really iron out the issues. Warm up exercises I consider as exercises to build you into the session to minimise the risk of hand injuries.
permit me to return the compliment
Hey, come on, let’s keep things civilised, ok? People come from different directions, look at things from different angles and may define terms in different ways. And on top of that, not for everyone on here English is the first language, which can further attribute to confusion and misunderstanding.
Concerning the original question: well, I just start practising/playing, call it whatever you want. But I’m still very much a beginner, so that may have something to do with it.
Well this thread took a bit of a weird turn…
It probably takes me about 15 minutes to warm up, as in, get to where I’m more accurate. The longer I play, the better I play.
For me, I usually start off by playing songs (or bits of songs) I know, then run through a quick bit of picking and scales. But if I’m just playing for fun, I’ll just pick up the guitar and start playing (probably 90% of the time).
Always a risk with online discussions, where misunderstandings can easily creep in!
I may not have explained myself clearly in the O/P - all I was trying to say was that when I first pick up my guitar and I try to play, say, 3 notes cleanly and at a reasonable speed, I can’t. However after a little time with the guitar, I can. Same 3 notes, same speed every day.
@twistor59
Well there you go, Phil - differences.
I find your 3 note scenario weird!
When I pick up the guitar I check the tuning at the 5th fret. I play it up and down, so that’s 12 notes. It involves fretting, picking and listening…and it’s music. I think of it as a necessity rather than warming up. How long does it take?…About 10 seconds if it’s in tune! (it nearly always is)
After that I play/practice, call it what you like. 
I am weird, it’s true!
It’s mainly a finger-sync thing. If I pick up the guitar first thing and try to play frets 12, 14 and 15 repeating with first, third pinky alternate picking at some reasonably fast tempo, like 144 bpm triplets say - a reasonably challenging task. I can’t. But after I’ve been playing a few minutes, I can do it no problem. So it seems it’s just warming up the neural pathways between brain and fingers.
Yep, that would be “reasonably challenging” 
I think you’ve answered your own question. 
In response to the OP… I don’t have any warmup period… my practice sessions are often very short, a few minutes at the start or end of the day & a few minutes here & there during the day. I just dive right into whatever the practice objective is.
In response to some of the “weird turns” in this thread I offer:
“Practice what you Preach & Preach what you Practice “ while respecting others & being kind-hearted at all times!
I remember that one of the earliest lessons I learned - which my wife & I taught our children was “If you can’t say something nice, KEEP YOUR MOUTH SHUT!!!”
This Community is exactly that - a Community which generally has a very welcoming, helpful, healthy feel. We encourage others, we welcome newcomers, & as a general rule, we RESPECT the opinions of others even when they differ from ours. This is the only forum I belong to because of the vibe we share…
All I’m going to say.
Tod
i wont comment anymore , promise 
I wasn’t pointing any fingers, I promise!!! (Especially not the “Driving Finger” as Justin likes to call it!!!)
Just wanted to add a gentle reminder that this is the nicest forum I’ve ever spent any time reading - flaming is pretty much non-existent!!!
I love that about you All!!!
Tod
Your comment was fine.