I'm not one of those users.
Here's a picture of my workshop:
It's my dining table, covered with an old curtain. I have a box of tools containing the following items:
- several small screwdrivers
- allen keys
- some small pliers, needle nose and flat
- two small wirecutters
- soldering iron, stand, helping hands
- some small needle files
That's about all you need to build a RepRap from a BitsFromBytes kit. Obviously, if you have a full-size workshop, things are much easier - but my RepRap sits behind the TV most of the time. Building from scratch or from a RepStrap would probably be a bit messier and needs a bit more time and equipment, but building from a kit can be done in your living room.
It helps a little if you can dedicate some space for a permanent setup (a boxroom or office would do nicely) but my RepRap is sturdy enough to get it out when I'm experimenting and put it away between times.