How much living space do you need?

Sorry it's been a while since my last post.  April is almost always an incredibly busy month for me.  Life--and the blog--should be returning to normal as the month concludes.

Unclutterer had a very interesting article today called "How much living space do you need?"  Erin looks at the amount of space given to prisoners to determine some bare minimums, but I think the most fascinating element of the article are the responses in the comments.  The answers are quite varied, between people who proudly declare 2000 sq ft "just right", those who have scientifically determined that 1100 sq ft is the bare minimum possible, and the RVers who find 300 sq ft way too big.

I found it difficult to answer how much space I need. 

Several years ago, my partner and I lived in a 200 sq ft studio after we scientifically determined it to be the cheapest apartment in downtown Portland, Oregon!  Functionally, it totally worked.  But we were living with a very naughty cat and after three months of very bad sleep in very close quarters, we swore "Never again!" to a studio. 

We subsequently lived in a 2000 sq ft house with 6 other adults.  I think such an arrangement only works if you're young or recovering from an addiction (don't worry, we were the former).  After this we swore, "Never again!" to roommates.

We then lived alone in a 500 sq ft, one bedroom apartment which was... fine... no problems.  We had a balcony big enough for a couple of chairs and an upside down tomato plant (DIY!), and the living room would fit a couple of guests on a couch bed.  No forswearing occurred upon move-out, but we really wanted a second bedroom to use as an office.

We now have a two bedroom, 700 sq ft apartment which I find incredibly spacious.  We both work from home about 70% of the time, and use our shared office very effectively.  My only yearning is for some outdoor space.  We still have the naughty cat (and have added a well-behaved stray into the fold), but the much bigger apartment makes them only minimally less disruptive in the middle of the night.

I seriously have no idea how much room children take up.  I like to imagine myself as a super-minimalist future mother, but recognize that I am probably delusional.

How little space have you lived in?  How much do you live in now?  Do you find yourself with too much or too little?  What aspects of your life factor in to how much room you require (for me--it's cats and my work schedule)?