What % time would you say you have someone at your unit that can fix most things?
At our unit someone's always here but we have older equip and a lot of repairs.

We run four patient shifts. There is someone onsite an average of 8-11 hours on weekdays and on call on weekends. There is also someone on call when no one is on site during the week.

Two techs, four clinics spread out over a large geographical area. We try to split the difference by hitting the two out of town clinics once a week. I come in early for start up at the main unit and my assistant comes in a little later so he can finish off the day after I leave. He pretty much takes care of the two in town units and I take care of the out of town units.
We trade off on weekend call. One weekend, off one weekend on.

3 units, 90 machines, 2 days a week each at the 2 bigger units, 1 day at the smaller. My supervisor takes after hours call otherwise I would have been long gone.