I lived one block away from Fitler Square for 20 years. Finding a spot during the day is easy. Finding a spot from 6pm to 1am is often very difficult. It helps somewhat if you have a tiny car, nothing bigger than a Honda Fit. Driving something even smaller - like a Scion IQ or Smart car - increases your chances of finding a spot.
Residential permit parking stickers aren't expensive, and are essential if you live here and don't drive your car every day. Without it, you *will* get an expensive ticket every time you leave your car parked in the same space for longer than 3 hours.