Usually check the interface status last been used by looking at the uptime of the switch first and then see when the last time the interface been access by doing the following
Show int f2/7
I then look the Last input and output values to verify when the interface last been used.
But I came across the following problem on a Catalyst 4000
Cisco IOS Software, Catalyst 4000 L3 Switch Software (cat4000-I9S-M), Version 12.2(25)EWA4, RELEASE SOFTWARE (fc1)
The interface show up but the input and show never
FastEthernet2/7 is up, line protocol is up (connected)
Last input never, output never, output hang never