I can usually tell by the sound. Haven't used the titanium needles but they definitely look interesting.
I wouldn't mind changing needles more often if they weren't on the expensive side. I did find a place online that sells Organ needles in bulk/100 for only $19 and have been thinking of buying them, then I wouldn't mind changing my needle often. Organ needles are supposed to be very good needles.
warm quilt hugs, sue in CA