This is totally logical, but psychologically hard. When I was a student I had totally-free online stuff I built lead to a stream of requests for upgrades, addi

This is totally logical, but psychologically hard. When I was a student I had totally-free online stuff I built lead to a stream of requests for upgrades, additions, bugfixes, etc. -- and the unreasonable ones are easy to discard, but some requests would be polite, friendly, and include offers to help. I'd agree to make the seemingly-small tweak, or accept the help, and then realize after a week that I didn't really have the time, or that my TO-DO list was being pulled completely out of whack.... Better to not publish your email address at all, perhaps, or make very clear that emails may be eventually read but very likely not responded to.