Known problem, if you are helpful some assume you have plenty of time.
- Often I respond by saying that when they post the same question on the forum there are many more people to help and that they will get faster and better answers.
- Unless the issue is interesting I feel free to take (much) time before responding ("Sorry, no time") just like normal e-mail.
What I find a bit annoying is that they often do not provide any link or so and they sometimes assume you still know their "project" while you see dozens ...