For me it depends on the items, on who's asking, on how they ask, and the amount they're asking for.
If somebody is always begging for (easily obtainable) stuff, they probably won't get anything.
If somebody spams the chat with "need food", "starving", but never actually asks whether somebody might share some with him, nope, not getting any. But if they say hi, i'm new here, would anybody have some food to get me started, or stuff like that, i might even go out of my way to get them a stack of fish or something.
If they need 1 item to make their build complete, i've probably got it.
Relatively rare items (packed ice, terracotta) i'll probably not give away, dirt or stone probably yes, if it's something i've just gotten lots of i might well give it away, bulk items which i had to mine (sand, gravel) probably not...
But yeah, it depends, and it always helps if you ask nicely ^^