I don't do availability checks for non-paying jobs. Because I don't say yes to any job unless I've read the script and I don't read scripts for availability checks. That's 2-3 hours of my time gone for a job I might not get. When you're early in your career and trying to amass credits, it's reasonable to work for free a lot until you get to know and work with folks in the industry which will lead to work that will look kickass on your resume.
However, once you've reached a certain point where everyone in town knows you, you got a press kit and website with hella NYTimes reviews, then it's time to make yourself a more valuable commodity by refusing to work for free. Because if you don't, you'll be working for free or for pennies for most of your career because folks have figured out that they can get you for cheap. Trust, I know plenty of theatre actors who are collecting more money than the rest of the cast....that's because they know their worth and are willing to pass on a job by saying no to little or no money. There's a certainly level of self-worth as a human being and an artist that those kinds of actors have learned to develop. After awhile, it doesn't feel frightening to know, it feels like a relief from some grinding work that no one was going to say thank you for, or make you an offer or pay you for your time. Actors who say no, are done proving and start getting better jobs and making significant money constantly.
For the record, I don't do availability checks when I'm casting a film or play. I simply cannot wrap my brain around asking an actor to hold time for me when I've not really chosen them. It's like saying, "I don't want you, but I need a body, so will you be that body." That's feeding on actor desperation which we need a whole lot less of ...(and that's on us to make our own opportunities instead of waiting for someone to give us work for hire)
The only exception is for Film/TV. Because those jobs are automatically on offer to folks who are already on TV shows or movies currently in theatres. So they're putting me on hold just in case they can't get an actor released from their rehearsal schedule. That has to do with viewership, audience, whether or not a network wants to cast from the shows already running and millions of dollars on the line. There is also thousands of dollars to be made from 2 hours on a set and you only have to read and study your scene (because most episodics don't give you the entire script until you book the role and are on set). I'll be on hold for a job that requires 2-3 hours of my time for potentially thousands of dollars and massive audience numbers seeing my work. From a business perspective, that a risk worth taking...it moves me into a much wider market place with the potential to make the kind of money that will change the fabric of my life.
Availability checks for theatre? Not so much, I have a 6 figure education that you're paying for, so if you can't make me an offer, I'm not taking time to read your script and decide. My agents/manager tell me it's not personal, it's just business. But you know what? My time is money, so my saying "no" to an availability check means I may lose valuable money-making time waiting for a no money job. So my refusal is business too.
My career, my dreams, my plans, my ability to make a shitload of money doesn't take a back-seat to the concerns of the industry....