Preventative care only. No sick patients. (If those present, you refer them to a local vet.) Additional advice can be given to clients at your option.
Cons
You have to plan these days a couple of months in advance. It does knock out weekend days when you might otherwise be able to do things with people who have normal working schedules. Support staff is variable; some are not as experienced, so you just have to be patient and help them learn.