What kind of compressor do you use @Fireball XL5 ?I find using a compressor before dirt allows you to run dirt/overdrive pedals "cleaner" and still get that type of sustain and tone similar to like you'd get with the amp's volume way up. Kind of like an AC/DC type of drive where there's a distorted tone, but it still reads as clean.
Using a boost pedal alone, you get a significant volume jump, but the notes distort and compress heavily on the attack and die off too quickly. Using a dirt/overdrive pedal alone, in order to get the needed sustain & compression like you'd get with a cranked amp, it requires an increase in the distortion/clipping of the pedal. Then the tone is often too distorted and unnatural.
Judicious use of a compressor before an OD/boost allows the notes to stay in the sweet spot longer without the accompanying added distortion that goes with increasing the gain of the OD pedal.