[poutine]

If you built a 1000sf detached home in North America you'd have a hell of a time selling it later on outside of some very specific conditions as it'll not be much cheaper than a 1500-2000sf home.

Home costs do not scale proportionately with their square footage. For example you still have one refrigerator in most homes regardless of size, one front door, pay base flat fees for services and trades just to show up, permitting fees, etc.

[anthomtb]

Along the same lines, adding bedrooms is basically free in terms of additional maintenance. Especially if you are not actively using them. All you will need to do is vacuum/sweep and dust in there once a month, maybe less often than that.

The only marginal financial cost will be energy required to heat and cool the space. Seeing as the original commenter is in the SeaTac area, with a temperate climate, one would think total energy costs tend to be low (I do not live there so I could be wrong).