Scenario: you're working through the backlog. You get to a Yamaha that's been in the pile for a while. Just as you get it on the bench, you get a phone call from a touring musician. He urgently needs a J-200 refretted as an irate fan attacked his fretboard with a brick. You decide to bump the guitar on the bench and get back to it once you finish the refret. Halfway into the refret, you get a phone call from the Yamaha owner asking how it's going with his guitar: what do you say?
"I'm sorry, I'm not yet able to get to it but I will let you know ASAP; One of my professional clients has an emergency with a very sensitive timeline that I must assist with."
Juggling pro and hobbyist/amateur clients can be tough, but I've generally found folks to be understanding. If you've had the gentleman's guitar for weeks on end and he's been inquiring about it the whole time, he may not be as sympathetic, but I've found that hobbyists often understand the notion that while they may WANT their guitar back within a specific timeline, a pro NEEDS their guitar back within a specific timeline.
I may offer a modest discount on labor to the delayed party if I feel that it's warranted, and I have a disclaimer that Express Service carries a 50% additional labor surcharge (obviously paid for by the party whose guitar is being shot to the front of the line). This surcharge helps offset any money lost from giving a discount to the person who got pushed back, and compensates for the "chaos factor" such jobs can bring into your life. I sometimes may not apply the surcharge but since it's on the books then I at least always have the option, and it gives me the necessary ammo to handle that "political" part of the job without much stress and without bleeding money.
I also tack on a whopping surcharge to be put next on the list, but I don't work fast, so I turn down the "gotta have it by Friday" jobs.
Hey, I'm only a talented local semi-pro, but I have backup instruments in case I have an issue with my main gigging ones. So I don't have a lot of sympathy with "touring pros" who don't.
Over the years, I've learned to shy-away from most jobs that start with "....and I gotta' have it back by (fill-in-the-blank)". Nothing but trouble there. Greg's right.... the pro players have backup instruments and if they don't, maybe they're not as "pro" as they'd have us believe.
If someone brings the instrument and I can look it over, we'll probably be able to come up with a time frame that's reasonable and mutually agreeable, but the customer's "emergency" isn't mine and I try to make that clear (in a nice way) before we settle on what work's going do be done and by when.
Also, if I know a certain job is going to take, say 4 or 5 days, I'll tell the customer a week. That way, if it's done early then I'm the hero! Plus, it allows for a little padding to get one or two of those quickie jobs in & out the door without going over the original time estimate.
Yeah, I do that fairly frequently, actually. I usually estimate a week to a week and a half for most jobs. Restrings are quicker, usually next day unless its a weekend, more complicated structural stuff can be longer. I offer a 20% rush charge to cut the queue, but I typically don't offer that for refrets or structural repair. But if I take on, say, a headstock repair or a bridge reglue, I might start that a day or two after it came in, to allow myself extra time if I feel like I'm going to need it.
On neck resets, or very complicated structural repairs, I say a month minimum, and those jobs get worked on intermittantly in the background while the day-to-day setup/pickup installs/nuts and saddles and stuff get done. I've got enough of a steady flow of small jobs coming in that I can't shut down shop and work from start to finish on something more involved, not to mention glue/finish drying times and whatnot.