Self employed

Let say I teach art workshops and make $500 -1000 in income per year.  I've written off business expenses for the past 3 years which have exceeded my income modestly each year.  I work at creating these workshops all year, so I'm a very active participant in the process. I just haven't attracted enough workshop attendees yet to turn a profit.    Can I continue to write off expenses that exceed my income?  My intention is to make money of course, but so far that hasn't happened.  I don't want to get in trouble.  My husband has a regular job.  This is what I do full time on the side.  I'm a self-proprietor doing a schedule c.  I read something about having to show a profit 3 years out of 5? I'm not sure if that is really true, but I want to make sure.