How many projects are too many?

I recently started in on a new project, all for the standard and good and decent reasons.

I've decided to write a memoir (ugh, I hate the word!) of sorts on the experience of living with Temporal Lobe Epilepsy. One, it's been eating at me for some time, and I most likely won't publish it, but I want to externalize the experience, and as a writer, this is how I process. Two, even among individuals with epilepsy, this is a rare form of epilepsy, and in addition my late diagnosis it makes the story even more compelling, and therefore, potentially marketable. So, yes, this is a personal project, and perhaps it's indulgent, but it simply feels good to do it.

My other projects are more straightforward.

I have The Depths of Memory three book series. The first book, The Dream Sifter, is written and out for query, the second, to be named is halfway done, and the third is outlined roughly. I count this as two open WIP's. (That's 'works in progress to you non-industry folks.)

Then there's The Chosen Few series. The first book, The Daemon Whisperer is about twenty percent done in rough draft, and the second book, The Madness Path, has a few scenes written. There's a third book I have rough outlined, but let's not count it as firm as of yet. So for now, two open WIP's in this series.

And I had this recent amazing dream which lead to a fully-fledged book idea. A ghost seeking revenge, creepy as all get out. I need to write it as a novella, and then rewrite it as screenplay and see if I can option it. No, seriously.

And when I'm not busy, I'd like to screenplay Ripples. Ohhh, yeah baby.

So yeah, if I can do the maths, I think that's about seven WIP's I'm got backlogged. However, there's only three I'm actively writing on and touching on a weekly basis, and all at different times. I work on the Daemon Whisperer while I'm commuting, and the Depths of Memory sequel in the evenings while I'm home drinking a favorite wine. My thoughts on epilepsy I record on free time over the weekends.

Frankly, sometimes if I get stuck with one story, it's nice to have another to go flex my muscles on, so I don't get to feeling stuck in a rut. But, like many writers, I don't have a problem coming up with ideas, so it's more an issue of coming up with the time to juggle life and all the writing I'd like to put out there.

What are your thoughts? Are there limits on how many projects a person can reasonably take on? Do you have difficulty jumping from one set of characters or universe to the next? Do you prefer to stick with a series through to the bitter end before starting the next one?

Oh, and most importantly, am I insane for considering sharing my personal insight on epilepsy with the world? Mind you, it won't be a doctor's view, just this humans. And bizarre insights, no less.

So, hit me. With your thoughts, comments, etc. Do you keep too many projects on your plate, or just enough?