Leaks occur in two common places: round the hose O-rings and through pin
hole corrosion in alloy parts.

Less commonly it leaks through the wall of old R12-type hoses.

Your 92 was built for R12 refrigerant When the compressor was replaced,  the
system may have been updated to R1134a, which requires new O-rings. If this
was done, there should be an update sticker somewhere, typically on the
inside of the hood.

Locate the high pressure valve on the tube that comes from the condensor in
front of the radiator. Press this for a moment.  If you get a loud, sharp
SHHH sound, the pressure is OK. If you get a quiet, soft shhh, you still
have residual pressure, and you can top up the system with Duracool or
similar compatible refrigerant for about $20

If you have no residual pressure, then you need to take the car to an A/C
shop because you can't do this yourself unless you have the right
(expensive) equipment.  Have them do the following.
a) replace all O-rings with R1134a compatibles.
b) if the system was still R12, pull the compressor off, replace the oil and
fit the necessary R1134a fittings, and replace the drier cannister.
c) evacuate the system (this is what you can't do yourself) to test for
leaks. If the hoses themselves are leaking, you will have to get new hoses.
d) refill with R1134a.

Get a quote from several shops. It should be in the $200 or so plus parts
range. No shop can tell the hoses are bad without running tests.

Stewart DIBBS