Dao
No longer a newbie, moving up!
Yes, I would write off money spent on lens, because all technology depreciates as time advances. If it meant I would be able to keep up with other photographers, and that is how I make my living. It comes a time in a business to cut your loss and advance. We have paid over a couple of $1000 for computer and software and then repurchased again a few years later to keep up with graphic designs.
You may not know, not like computer equipment, the good quality lens won't depreciate much or sometimes it increase its value.
2 to 3 years ago, a used Canon EF 70-200mm f/2.8 L IS USM lens in great condition cost around $1300. But now, it is hard to find one cost $1300. They usually cost more. And a new EF 17-40mm f/4L USM lens cost around $600 few years ago while the used one around $500. Guess what the price of a use EF 17-40mm f/4L lens is, around $600.
And I am sure a $1300 computer bought in 2008 may cost less than $300 now. And I think for business write off, computer equipment only have 5 years. (please correct me if I am wrong). So I believe if a business donate a 6 years old computer, it may not able to claim anything. However, a 6 years old EF 70-200mm f/2.8 IS USM lens still worth at least $1300 if it is in great condition. (even if the purchase price back then was lower than $1300)