You might have the ROI question upside down. The overhead of developing for IE - even older ones - is small if you ignore bells and whistles. There are a few CS

You might have the ROI question upside down. The overhead of developing for IE - even older ones - is small if you ignore bells and whistles. There are a few CSS gotchas to worry about and that's about it. A webpage shouldn't require megs of JS and assets and what have you to work. The real question is whether the time you spend on these bells and whistles contribute a positive ROI.