Personally, I'm on the 'she-shed' side. You could even build it in a way that you could take it with you if you were to move (like those tiny homes that are on the news a lot). No real stairs to deal with, but it would mean dealing with the winter weather. Hopefully you get less snow this year!

Here's a picture of my inspiration for what I want to build for a long-arm machine. I'll have to wait until my daughter is finished university (she's 4 now). But I can still dream...
http://www.fourlightshouses.com/blog...e-march-day-28

My immediate thought, too. No stairs, but still....it's outside....in the cold.....and you'd have to have a separate heat source, wiring, plumbing (perhaps). Addition is the way to go, imo.

An addition would be awesome! It's a win-win because it adds to your house square footage and you don't have to go out! How close to heaven is that?

Interesting discussion--but think you need to keep a couple of things in your research: what are the zoning restrictions in your community--sometimes a shed is allowed only without utilities, heat, etc? Would an addition to your home be cost effective in your neighborhood--basically would an addition large enough for a long arm and other sewing be so expensive and not be recouped in a home sale? Would you have to update the rest of the house's electrical if you add a room? Is your lot large enough to meet the requirements of an addition? Or a "she-shed"? Obviously with a shed, you would have to have electricity--what about plumbing? It does sound like you need to make some changes due to the stairs and falls--that is a no-go for sure! I sew in my daughter's former bedroom where I've moved out furniture, added laminate flooring and it's mine! And the long arm is located in the finished basement which is shared as a rec room that gets little "rec" since kids left home! Nice thing about both is that both levels have a bathroom and storage. My thoughts are that if/when my knees really do quit (I've replaced both knees once already)I'll go the route of chair lifts. The other nice thing about the basement is it's a walk out so I can walk outside to get to it if needed.

Addition would add to value of house , if you made a workshop room instead of shed can be selling feature

When my husband was growing up on the farm he and his brothers shared the attic as their bedroom. It was accessed by a pull down stairway. I would wonder if that type mechanism couldn't be employed inside the garage for access to your sewing room. I'm sure that redesigning access (and a covered walkway from the house) would be far less expensive than new construction.

if I had the option, I would go with addition, it will make it easier to go back and forth doing chores, unless you have someone to do your chores then I would like the seperatness of a she shed