Why have a guy per 15 companies. What happens if that person is off sick for a week? or even if that person decides to leave suddenly? Also you manage the budgets yourself for each of the companies? Funny way of doing things! 10-20k should just be for the support contract of 24/7 support, time onsite should be charged per hour extra. 15 companies should be bringing in around 250k a year. Worth having 1 guy per 5 companies to take the load off and being able to work on other projects. Sounds like a risky business model.
Money. The more clients a guy can take on the more money they make. I would say I'm bringing in about $200K in billable time per year. We advertise 24/7 support and have one guy on call every week, but there very few calls after hours. I don't have any clients that run 24/7 so it's mostly people working from home or travelers in other time zones that I get calls from once in a while. It is an issue when someone leaves or is sick, but they have been doing it like this for many many years and are comfy with their business model. When a tech leaves a client or two will drop, but the majority of that techs clients will be moved to another tech. There is a pretty high turnover rate. Most guys can't drive 90% of the time and be eating lunch in their car 4/5 days a week. I've gotten used to it and it has become a routine, but I'm on the market looking for something more grounded.