何时停止关注浏览器

The question is simple really, when is it time to finally pull the plug on a browser version and just not care about supporting it any more? As can probably be expected this is in regards to IE6 specifically right now. A site I'm working on right now has a mostly-finished design that needs to be integrated but most of the back-end functionality isn't expected to be done for another 6 or 7 months. Is it really worth fighting with IE6 as apposed to just skipping it and supporting IE7+ instead? Also, the site in question is targeted specifically at photographers, many of which I know for a fact are mac-heads.The question is simple really, when is it time