Best way to repeat on a timer?

[RGould8]

I've got an app that needs to poll the user's network settings every 3 seconds.  I'm presently doing this by calling a unix command via the shell command in Revolution on Mac OS X.

The problem I'm having is that, while this seems to work, it makes dragging the application window very jittery when the app is running.  I suspect this is because I might be creating a memory-hogging timer loop.  Here's what I'm doing:

on opencard
     send "checkstatus" to this stack
end opencard


on checkstatus
     put shell(unixcallgoeshere) into field "status result"
     send "checkstatus" to this stack in 3 seconds
end checkstatus


The unix call I'm using spits back it's result instantaneously, so there shouldn't be a backlog via the unix side of things.  Is it bad to have a handler call itself via a timer - - - does that create some sort of "nesting" problem?