Joel Spolsky had this to say about the chairs, and I agree with him:
Let me, for a moment, talk about the famous Aeron chair, made by Herman Miller. They cost about $900. This is about $800 more than a cheap office chair from OfficeDepot or Staples.
They are much more comfortable than cheap chairs. If you get the right size and adjust it properly, most people can sit in them all day long without feeling uncomfortable. The back and seat are made out of a kind of mesh that lets air flow so you don’t get sweaty. The ergonomics, especially of the newer models with lumbar support, are excellent.
They last longer than cheap chairs. We’ve been in business for six years and every Aeron is literally in mint condition: I challenge anyone to see the difference between the chairs we bought in 2000 and the chairs we bought three months ago. They easily last for ten years. The cheap chairs literally start falling apart after a matter of months. You’ll need at least four $100 chairs to last as long as an Aeron.
So the bottom line is that an Aeron only really costs $500 more over ten years, or $50 a year. One dollar per week per programmer.
A nice roll of toilet paper runs about a buck. Your programmers are probably using about one roll a week, each.
So upgrading them to an Aeron chair literally costs the same amount as you’re spending on their toilet paper, and I assure you that if you tried to bring up toilet paper in the budget committee you would be sternly told not to mess around, there were important things to discuss.