Compressor, my guitar's closest friend - The Chain Gang #4

There are three big reasons why I love to use a compressor as the first pedal in the signal chain:

1. To get the strings to equal volume.
2. To get the pickups to equal volume.
3. To push the pedal that comes after the compressor.

I like to play with my fingers most of the time. Now if you pick several strings at once and you don't have the perfect technique down all of the time, chances are that the strings will not sound equally loud and might not ring out equally long. The compressor mitigates volume and sustain differences for me.

I like to mix and match pickups on my guitars which often leads to huge output differences between two pickups.
So let's say you like the sound of two pickups working together in the middle position of a humbucker guitar but if you switch to one single pickup position, there's a change in output.
Now that may be exactly what you want, you might get a higher output and have an instant lead switch on the guitar to get a volume boost for your solos - say you play rhythm in the middle position and then switch to the bridge pickup for your louder leads.
Yes, I know that you can also try to even out the volumes of the pickups with the screws but that will only work as far as the turning of the screw goes and maybe you already found the perfect sound of your guitar in the middle position and don't want to change the height of the pickups around anymore.
So if you really just want to change the tone of the guitar without the increase or decrease in output, a compressor can even out the output differences of your pickups.

I like to use the classic compressor - overdrive - combination. You can use the compressor for a nice clean sound, use the overdrive for rhythm and engage overdrive and compressor at the same time for a lead sound. Stacking compressors and overdrives gives you a nice push in drive (not necessarily volume) and it enhances the harmonics of the overdriven signal.
So with say a single channel amp and two pedals you'll have the core sounds covered.