When your software breaks, how quickly do you expect the programmer to respond to your request for assistance?
Okay, that’s probably too broad. We both know that it depends on how broken it is.
The software I build for my customers is an integral part of their business. It might be their money scoop. Or it might run their day-to-day operation. Regardless, if it isn’t working at all, it affects their bottom line pretty quickly.
On the other hand, if it is minor bug that only affects a limited number of transactions, it probably isn’t an emergency.
Assuming it is ...