I would first evaluate how much work would be involved with making their design pixel perfect. There are some platforms where making certain things pixel perfe

I would first evaluate how much work would be involved with making their design pixel perfect. There are some platforms where making certain things pixel perfect is extremely difficult (Sharepoint customization for example). I would also give my customer feedback on whether the UI helps them achieve their goals. Sometimes people zero in on a visual design that has poor usability, and all you're doing is taking them further down a bad road.