If you have a charged system and the compressor will not engage, did you try unplugging the pressostat and jumping the wires? Just use a paper clip to jump the 2 wires with the engine running. It is possible that the pressostat is at fault if the system is fully charged.

If the clutch gap is too large at the compressor, the clutch can be shimmed. You can use a feeler gauge to check the gap, anything over .030 is bad. If you shim the clutch, you can get it down to .010 without any problems.

One doesn't normally replace the compressor until there is bearing noise with the compressor running.

IF you replace the compressor, it is probably a good time to replace the receiver/dryer tank. Yes, you will want to remove the wheel for better access unless the car is on a lift.
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Keeping it running is better than buying new