The problem with college guys is that they are a short term solution. They may be off in the summer, but what happens Aug.-Sept. when school starts again. Also, its not really worth it to invest in much training because they won't be with you more than a few years. Turnover costs kill small companies. Focus on hiring people that have the potential to stay with your company for years. I'm only 24 and work a lot of guys older than me. I wouldn't hesitate to hire someone older. I have some friends still in college that I use on big jobs in a pinch, but for day to day operations I have people committed to my company.