I just changed my compressor clutch/pulley last weekend as mine was going out along with an o-ring leak.
There's a 10mm bolt, two snap rings and I use a mallet to remove the pulley. The replacement kit came with new hardware: 10mm bolt, snap rings, washer as spacers, pulley, clutch, magnet. You would have to use the provided washers to adjust gap between the pulley and clutch as I had to use 3 to get the correct clearance. There's a couple of good videos online for reference.
I bought the replacement pulley through Ebay and this took about 45 min to do including taking off the pulley twice to adjust the clearance. You can see the pulley assembly on my IG account @jcspecbgsr (IG is still down btw cause big tech).
To tell if your compressor is going out it will be the black oil of death as some calls it. I have an o-ring leak so I can safely remove my high and low pressure lines at the compressor. If you have refrigerant in your system, you would have to take it to an AC shop to remove it safely. This stuff is pretty nasty one your skin/environment. Once your system is empty you can unbolt the high and low pressure to see if you have any oil residue. If you do then your AC compressor is going out. You'll have to flush your entire AC lines to clean it out or you'll ruin your new compressor.
Hope this helps.