When is it worth it to pay someone else to do the work?

Deciding when to pay someone else to do something for you is a very personal decision.  I don't mind paying to have my husband's shirts laundered because I hate to do it and have never gotten the hang of getting wrinkles out of the sleeves.  I'll pay to have the gutters cleaned because my husband and are both afraid of falling off the roof.  I'll pay to have my hair and that of one of my sons cut because I can't cut hair well, but I use the clippers on my husband and the younger boys.  I'll pay for inexpensive breakfast cereals because we get bored of the few breakfast items I can make well or I just haven't gotten around to making up a big batch of something.
I'm a stay-at-home mother, so my income is generally zero.  So, it makes sense for me to do a lot of cost-cutting things that it wouldn't make sense for someone working full time to do.  I thinks its important to decide how much time and labor you're saving by doing a task yourself, as well as how much you enjoy or dislike a task.  I know people who consider housework therapeutic and would never hire someone to do it.  I will never be in that bunch, but I do feel that since I am at home, the cost of having someone else clean the house is too high.