Just how far into the past do you personally go in coding support for legacy web browsers?
Personally, I code only as far back as about 5 years or so, particularly when it comes to Microsoft products. For example I am tending now to drop support for I.E. 8 and earlier and I tend to put something on the web page that says something along the lines of "You have a crappy old web-browser, upgrade it already!!"
Nevertheless, I still get emails to admin along the lines of "Your website doesn't work on my steam-powered computer running IE 1.0!"
I believe that trying to support everything since Noah's Ark was built is a waste of time. For example, if I went in to my local motor spares store and asked them if they had a windscreen wiper for a Model T Ford, they would probably laugh at me! Same philosophy goes for software.