Kids:staying alone

At what age did you start leaving your children alone?
What about only children?
What is the longest that you're comfortable leaving them?
What about coming home to an empty house after school?

For working out of the house parents:
What do you do about after care...and do your kids come home alone and
what age are they?
What do you do on school holidays, half days, summer vacations?

I suppose that this topic has been beaten to death...but it has all
been before my time. I have some feelings on all of these questions
but most of my thoughts are battling with each other.

I was just offered a full time position with an agency that I've been
contracting with. I'm not getting any younger and I fear that if I say
no, the opportunity might not present itself again. I also know that
my daughter's needs come first. As long as she is in school, I'm
covered. But they have so many darned days off/half days and long
weekends....

I feel that contrary to some popular beliefs, it is crucial to be
around kids entering adolescence even more. Testing the waters without
a parent home could have a devistating outcome. At least in 6th grade
most tweens are too scared to do anything totally stupid. I'm up
worrying about what to tell the director tomorrow afternoon.

And if it makes any difference to your response: I'm a married, single
parent. Husband is rarely home; workaholic. I've been primary
caretaker for 11 years in most aspects of her life.
Being offered this job did not result in positive dialogue between my
husband and I :-( I'm hoping to get some feedbacka nd input from you
guys.

TIA