Dan, I'm surprised that you never asked before. Several of us have experienced the same thing.
People who receive a product gratis, tend to be patient about asking for help with it (some Orbinauts are exceptions). When
they pay for it, they demand exceptional service. An independent will usually provide, though the big corporations don't.
There will come a time when you will have to sit down and calculate the cost effectiveness of this additional service you
offer. If you don't, the demands will baloon until they fill all the time available and more. If you haven't already, start
a new forum dedicated to aspects of your product and let the fans who rave about it help you out.
Remember, there has to be time to hug your children, listen (?) to your lady, watch the clouds and pretty girls ...