I've recently quit my full time developing job at mega-corp, and I decided that I'll look for a part time job. Since then I've talked to half a dozen potential employers, and every one of them had the same reaction when I said the magic words "part-time" - they all closed up and became suspicious. Now, I understand that it might just be me, so as control I asked every one of them what if I were willing to work full time, and they all said I would probably get an offer.

My question is two fold:


Why, as an employer, would you give up a competent, even great, developer, simply because he wants to work 3 days a week and not 5?
How do I sell the story of part time job better? I usually just list my reasons which are that I prefer that balance currently in my life and that I want to work on my own projects, but it leaves them even more suspicious - am I going to start something myself and quit? Am I just lazy?



  Why, as an employer, would you give up a competent, even great, developer, simply because he wants to work 3 days a week and not 5?


More than one reason (all argued from the point of view of an employer):


As Fred Brooks argues in the book The Mythical Man-Month, the efficiency of a team goes down as the team size grows, because the amount of communication grows faster than linear with the team size. So N full-time developers are far more effective than 2N part-time developers, at the same cost.
If the developer is working on some important system, you want to be able to reach her at least during normal business hours. 
A full time employee spends only eight hours at the office five days a week, but his mind is really working for the company 24 hours a day, seven days a week. That's why you sometimes wake up in the morning with the solution to a problem that's been bothering you for days - your mind doesn't stop working the moment you leave the office. For a part-time employee, I would fear the opposite: Instead of thinking about his day-job at home, I'd guess she'd think about her private problems at work.



  How do I sell the story of part time job better?


Actually, I think the employers are mostly right, so I don't think you can "sell" it much better. But you could find a small company that doesn't have enough work for a full-time employee. They might be interested in hiring you part-time. Jobs like that probably wouldn't be very glamorous (or well-paid), though.

EDIT:
Your comments suggest that your don't have much working experience and that you can't imagine spending 40 hours per week at work. I can totally relate to that, sitting 40 hours a week in the cubicle next to Dilbert and Wally does sound like a horrible prospect.

If that's reasonably close, forget my advice about looking for a job at a company that doesn't have enough work for a full-time employee. These jobs certainly exists, but you won't learn much there (if they have only one part-time developer, who would teach you anything?), and they don't look very good on a resume (why did he start his career doing that? Couldn't he find a full-time job?). They'd probably be rather boring jobs, too, and IMHO spending 20 hours a week at a boring job is worse than spending 40 hours a week working on something you care about.

Instead try to find a full-time job where you get to build something interesting, where you like your co-workers and where you genuinely like going to work each morning. These jobs really are out there, and they're easier to find than part-time positions. There's still enough time to play StarCraft at the weekends ;-)
