I charge by the hour. I am thinking of charging the client $1000/month in addition to my billable hours for my 24/7 availability.
One more thing to consider: I am the _only_ developer. The bus factor here is 1. If they lose me, they are going to be in serious trouble to keep their business running long-term. I mention this because I want to make sure I'm not extorting them (i.e. "pay me more money or I'm leaving and you're screwed") and also so it doesn't _appear_ that I'm extorting them.
My questions:
* Is $1,000/month a reasonable amount to bill for 24/7 on-call availability?
* Does this seem like extortion to you? If so, how can I make it less so? I don't want to extort my client, I just want to be paid for this considerable burden that's been added to my life and that often doesn't take up many billable hours.
Thanks!
P.S. I'm in the USA
You should look into Jonathan Stark [1], he talks a lot about "hourly billing is nuts" and how to think differently about how you work/think about your time. For example:
https://jonathanstark.com/how-i-realized-that-hourly-billing...
$250 per call out instance, plus,
$250 per hour under active call out, plus,
Day rate + $250 for weekends and other public holidays on call.
In comparison I think $1000 is very reasonable, but of course the circumstances may be very different.
Also, I don’t suffer alone; we only provide oncall off hours if the customer can as well.