With a "stick", if the engine speeds up but the car doesn't, the clutch is slipping.
Having the clutch disengage at the top of the pedal travel (instead of part way down as normal) as mentioned is another sign of a worn clutch.
Oil dripping from the "weep hole" at the bottom of the bell housing would imply a leaking main seal of the engine which should be inspected when the clutch is replaced in any case. (the odd drip isn't tragic, but noticeable leakage would need to be fixed)
The city driving mentioned certainly COULD shorten the "normal" life of a clutch, depending on driving style & how much "stop & go" driving was involved....