This should be obvious to everyone, but you’d be blown away by how many private shops I’ve walked into that don’t have a fire extinguisher available. Maybe they have one, but it’s hidden in a closet somewhere. Either way, it’s incredibly dangerous to do pretty much any kind of DIY work — especially woodworking and metalworking — without some way to put out a fire.
There’s a lot to understanding which extinguishers work best with which type of fires, but if you’re living without one while you’re all tied up figuring it out, just run down to your local big-box and pick up a class A, B, C unit. It’ll be far better than nothing.
If you want to know more, there are some great resources on the net that explain things in detail. But my piece of advice to you today is, don’t wait until you have a fire.
Oh yeah — one other piece of advice: Don’t mount the fire extinguisher in exactly the place where you think the fire’ll start. It really sucks when you can’t get to the extinguisher because it’s on fire. Doh!