Will work for...?

I love to talk. Anyone that knows me, knows that unless they have an extra 5 minutes to spare, they shouldn't start up a conversation with me if they're in a hurry.  I may talk your ear off.On that same note, I love to talk to groups. I have taught groups (large and small) about nutrition for several years ranging in topics from aging to weight management.  It is a great feeling to be seen as an expert in my field after 25 years, and I take great pride in it. While I may repeat a lecture, I spend hours pouring over slides and images to get the right information to the group I'm presenting to.What is upsetting to me lately, is to be asked to speak for free- over and over. I get it- we all have gifts to share and should give our time and talents when we can.  But, where do you draw the line on sharing your talents when you've got mouths to feed at home?  They say it's to "get your name out", but what if my name is already out there? Is the person asking me to speak working for free?  Probably not.I feel as though I am doing my profession (and myself) a disservice if I constantly volunteer my lectures for free.  Sure I don't mind talking to my daughters' scout troops or volunteering at my church or school.  But when a company has over 500 employees with money in their pockets to run health fairs and other incentives, they can certainly pay a seasoned professional to do a one hour lecture. 'Nuff said.