I just did a repair job on one of the first Woodward bags I made over a year ago.  It's owner, a friend of mine, is an ideal product tester.  He uses the bag all day, every day both as a backpack and a pannier.  He loads it up too heavy to carry on a regular basis, and isn't gentle on it in the least.  I'm pleased to report that the wear on the bag was pretty minimal.  After two winters of incredible abuse, all the straps, hardware, and seams are still intact and holding strong.  The only real damage was a zipper on the back flap.

shot of woodward backpack pannier with broken zipper

There are also the usual scuffs and smudges.  You can see where the fabric is worn down slightly from wearing against bicycle parts.  Aside from the dirt, this is still a great looking bag!

The zipper problem was caused by the fact that the back flap was an older design, in which it flipped around to the front for use as backpack.  That corner was under a lot of stress, being tugged apart with every conversion.  The current design has the back flap simply folding back underneath the backpack straps, greatly reducing the stress on those corners.

Now I have him testing out some new ideas which will hopefully make it into the next redesign.  I'm also getting a lot of great feedback from other convertible owners.