I think everyone's answer will be different.

In fact, I bathe more when I'm about to get really bad. Because it's literally all I want to do - even though it doesn't help, I always hope it does.

It can range from when you stop grooming yourself, to when you lose your appetite entirely, to sleeping all the time. Generally, when I'm worried that I'm getting bad, I am getting bad. However, everyone suffers depression differently.

My earliest warning sign is not moving at all. Just lying in one spot for hours and hours, without even twitching. Following that will be apathy, loss of interest in doing anything (even getting out of my room), and excessive bathing while ignoring the rest of my life. Basically, total isolation. When I isolate from my dog, that's when I know the suicidal thoughts are coming.