Bought some cheap developer once and it smelled like old socks, never again.

Totally, you have to check. I got caught last fall because I didn't. Was supposed to be a quick hike, sunny all day. Ended up in a downpour that soaked me to the bone, just like hart.tara said about that downtown flood. My own fault for trusting a clear morning sky. Now I check three different apps, it's made me paranoid. Don't you find you just stop trusting a single forecast after something like that happens?

Yeah, checking the ordinances is key. A lot of places have quiet hours that start way earlier than you'd expect.

Check the basics first, like @lunah86's caps lock.

Yeah, that's exactly why I won't touch a big room without the power stretcher. Had a call last year for a living room full of ripples, same deal. I just showed the client how the carpet had zero tension by lifting a corner, and explained that the first install was basically just laid down, not locked in. Told them the re-stretch was a full reset, not a quick fix, so it takes the same time and care as a new install. They got it once they saw the problem up close.