There are kinds big step/jumps as the size of a company goes up.
Step 1: You start out with the founders being on call 27x7x365 or people in the first 10 or 20 hires "carry the pager" on weekends and evenings and your entire company is doing unpaid rostered on call.
Step 2: You steal all the underwear.
Step 3: You have follow-the-sun office-hours support staff teams distributed around the globe with sufficient coverage for vacations and unexpected illness or resignations.
Step 1: You start out with the founders being on call 27x7x365 or people in the first 10 or 20 hires "carry the pager" on weekends and evenings and your entire company is doing unpaid rostered on call.
Step 2: You steal all the underwear.
Step 3: You have follow-the-sun office-hours support staff teams distributed around the globe with sufficient coverage for vacations and unexpected illness or resignations.