For many years I convinced myself that I didn't need a compressor pedal, but this video of Paul Gilbert encouraged me to try the Philosopher's Tone pedal.
Here's the deal. If you're the type of person that glues the volume knob on your guitar at 10, this blog is not for you. But if you understand the volume knob is the most important component in your setup, then keep reading.
The volume control on my Suhr Modern guitar has a treble bleed circuit built in it. This circuit makes high frequencies bleed into the signal as the volume knob approaches zero. Most guitars sound dark and muddy when their volume is turned down. Guitars with a treble bleed circuit can produce a nice semi-gritty chime-like sound when the volume is around 2 or 3. But one side effect is that the overall output volume of the guitar is low.
A compressor pedal like the Philosopher's Tone raises the output volume of your guitar when the volume knob is turned down. But here's the best part, when the guitar volume is on 10, the Philosopher's Tone pedal doesn't alter the sound much. Compressor pedals essentially change the role of the volume knob to act more like a second channel on an amplifier. This is great if you prefer the simplicity of a single channel amp.
Guthrie Govan stated that he doesn't use a compressor pedal because he prefers to let the power tubes in a tube amplifier do the compression. In order to drive power tubes into compression, power tubes have to be driven hard, which generally means your amp has to be loud. A compressor pedal allows me to get the sound and dynamics from a tube amp at a much lower volume.
I used to perceive compressor pedals and whammy bars as being gimmicks of the trade and not really necessary. My opinion has totally changed. These devices are tools that can greatly extend the craft, however these tools can be misused or completely ignored if not fully understood.