Looking for children under a certain age is more or less a full time job. Trying to mix it with work is, well, simply a bad decision.
Over that age, and if the kids themselves can manage it... sure, it's great. You're there for breaks and emergencies - much better than being absent for the whole day.
Over that age, and if the kids themselves can manage it... sure, it's great. You're there for breaks and emergencies - much better than being absent for the whole day.