As a n00b decades ago I used to have one or two to stay loosened up for a gig, but I'm long past that. The advantage to age/experience is no more stage jitters. Full disclosure: I mainly live in the bar band world, and did get nervous playing a theater gig with an all original band I work with, when we opened for Pat Travers band a few years ago. But these days I'm self-aware enough to know that a beer or more would not have helped me there.
Yeah; I started playing out in the '70s when the culture leaned heavily into drinking & drugging. I was nervous and imbibed in both. It took the edge off, though didn't completely mask the darker side of playing the college-town-and-white-boy-meth circuit.
Before getting clean and sober, alcohol/drugs no longer worked to relieve fear despite consuming dangerous amounts of both;
Nervousness had long been replacement by resentment and anger.
These days I mostly feel pretty comfortable and I try to avoid feeling angry, especially about crap I've got no control of.
On subs and pickups, I show up prepared and do a decent enough job to get callbacks. On my weekend gig, the drummer and I are both sober and help provide a consistent, respectful level of musicianship. On my Tuesday night gig, I back a rotating roster of special guests, all of whom seem happy when it's their date.
I'm not a teetotaler, but rarely drink at home or at the gig. The main reason is that alcohol is unhealthy -- claims to the contrary are false (not shaming anyone for imbibing; I don't always eat well). A practical reason: we musicians (along with bar staff) have targets on our backs when driving home so late, and I have been pulled over a couple of times on the way home from gigs. One of those times I'd had a couple/few beers and was into buzz territory, but walked a straight line. The next time I was completely sober, and it was a huge relief to have no worry at all about failing a sobriety test.
By design, field sobriety tests are hard enough to pass sober.
Last but not least, there's musicianship. I work with a whole bunch of bandmates in a bunch of bands. Fact: those who play sober are FAR more likely to perform well at the gig. Not everyone who drinks at the gig performs poorly... but some do, 'nuff said! The unfortunate reality is that those performing less than their best due to alcohol have no clue that it's happening. I'm not even talking about obvious mistakes that are cause to terminate... just the casually sloppy playing that the audience won't notice, but the rest of us onstage will. Part of the challenge here is the bar band mindset of "we're not getting rich from $100 a night, we're entitled to have fun with our hobby, the audience is also drinking and having fun, so no harm no foul". I guess that's fine if everyone's on board, but I prefer to work with musicians who put the performance first, even at casual bar gigs. Even if the sloppiness doesn't happen until the 3rd set, I still find it annoying.
The only consistent thing both alcohol and drugs did from early to later days was to make me a sloppy, inconsistent player - There are thousands of hours of live recordings to back this up.
When I recall first not being able to regulate my drinking once I took that first drink of the evening, we had a house band gig at a popular, center-of-the-universe Dallas bar. Even back then I
knew I wasn't going to be able to execute any kind of complex songs by the end of the night. My solution was to volunteer to put together the set lists, putting all the easy, 2 and 3 chord wonders in the last set.
I find it annoying as hell and damn near unlistenable hearing those last-set recordings from 30-36 years ago.
12 years ago when I was in the thick of it, despite having had 20-25 additional years experience playing out in the interim, my playing consistency was impaired.
