I'm a lawn newbie from Rhode Island. We bought a house and I focused on the backyard where the kids were (and neighbors couldn't see me "testing"). The backyard was lush and awesome until our cesspool failed and we had the yard dug up for a septic. So I started over, not realizing what crabgrass actually looked like until it was way too late. However this year the yard came in very nice because I over-seeded and fertilized last fall.
Photos include last year + this year photos of front, and last year of back after septic (you can see the border where my perfect lawn was before the mess LOL)