Knowing that you're getting sick is certainly is a precarious situation to be in. I've always found that contacting the venue right away and letting them know the situation is the best thing. They are used to this. Every club owner prefers to deal with things differently. Some will demand you play, others will get right on the phones to get a fill-in, and even others will insist that you find the fill-in. Here in Nashville, there are thousands of acts who could fill in at a moment's notice, and many of whom could send a blast out to their mailing list and light up their social networks to bring in a last-minute audience in. All of that said, here is what I suggest:
1. Contact the venue as soon as you think there is a chance you'll be too sick to provide a decent show. Tell them the whole story and ask how they want to handle it. I would emphasize that if they allowed you to cancel, you would help find a replacement so the venue would not go dark for the night. I would also explain that you can't, in good conscience, promote the show further knowing that you wouldn't be able to do it justice.[Judy adds: Consult your doc and vocal coach to help you make this choice.]
2. Try to have an act 'on hold' in case you have to cancel the day of or the day before. Try to do that before calling the venue so that you can present them with some real options.
3. Consider bringing in an opening acoustic act for the 1st third to half of your show. This will cut the amount of time that you have to personally perform.
4. If you perform at all, sell CDs and merch. This can help you offset costs that you can't eliminate, such as travel and paying the band members etc.. This is an important reason why every artist needs to have residual incomes and a reserve fund.
5. Watch out for legal implications. Did you have a contract with the venue? What does it say about cancellations? Hopefully it has an 'Acts of God' clause in it that gives you the right to cancel if you are too sick to perform. The last thing you want is to end up in a legal battle over the gig.
6. Make a careful choice between the importance of this one gig and the chance that you might blow out your voice for the next month, especially if you have other gigs or studio vocals lined up.
[Judy adds: Vinny, you help everyone have amazing days, man... thank you for sharing your wisdom with us here!] To 'All Things Vocal' readers: If you are a songwriter, do check out Indie Connect's Virtual Songwriter Showcase, Sept 21 - 22!I hope that helps. Have an amazing day! - Vinny