I bought a set of four chairs from a neighbor’s yard sale over a year ago. The seats had been covered in a horrible 80s-era tapestry fabric. When I removed the fabric, I found stained, white canvas underneath. The canvas was a definite improvement over the tapestry, but no amount of cleaning could remove the stains. Recovering the seats was the only option.
I picked up a couple of yards of blue canvas from the Alameda Flea Market (paying only $1.00 for the entire length!). Recovering the seats was pretty simple, moderately time-intensive, and very satisfying.
Here are a few photos of the entire process (minus the part where I cut the fabric because I forgot to take photos):

The “before” photo. You can’t see how dirty the seats are here.

Tools: flathead and phillips screwdriver, needle-nose pliers, staple gun, staples, newsprint to catch all the staples.

I removed the staples using a flathead screwdriver and needle-nose pliers. Removing the canvas revealed batting in good condition.

Ooh la la – a chair without its seat looks very naked.

Stapling the new fabric in place. It’s best to staple adjoining sides and move around the seat, rather than stapling opposite sides.

Screwing the seat back in.

The end result (the blue of the fabric is much more subtle than the photo would lead you to believe)!

All four chairs around the table.
Total time investment: 2.5 hours (plus 16 months of thinking about reupholstering the chairs)
Music to reupholster to: Actually, an audiobook, “The Tipping Point,” by Malcolm Gladwell
Oooh, your *new* blue chairs look so beautiful. I love that you included the “16 months” of thinking time. Well worth it!
– hillary