I don't think we can count on anything, even depression, as staying the same. Time moves on and situations around us change, as does our physical body. Sometimes we have a "week" of rain, and other times, only an hour; no way to tell when/how much our spot will get.

I was having a horrible time with a romantic breakup, I'd been involved with the man for a couple three years at least, and couldn't imagine life ever getting better, as it seemed it had fallen back into previous untenable levels, lower than low. Somewhere in there I had to get a job (part of why life was so bad, I had been out of a regular job for over a year and losing money/not making ends meet) so did and started it. The job was interesting enough but coming home still was not and caused a crash. Then a man I met on the job and I got romantically involved and life began to change dramatically. Five+ years later we married and now, 20 years beyond that, I consider myself living happily ever after. Didn't happen all at once or just as a result of the new love; I had 9 more years of good therapy in that 20 years and both my parents, an important mentor, and some good friends/other relatives died.

You can't tell when a thought, interest, job, person, situation is going to blow in like a cool breeze and shake up your world so it starts to move in another, "better" direction. I only know from my own experience to hang on tight and wait for the opportunity I recognize as being a start of a better way of being for me.