You can't make a data based decision without data. What you can do is test on an individual basis. Companies have been doing this long before computers came al

You can't make a data based decision without data. What you can do is test on an individual basis. Companies have been doing this long before computers came along. Look up videos by Steve Krug on how to properly run user testing. There are a lot of tools geared toward this already. Some offer testers, others just give you the capability to test with your own anonymous users. My rule of thumb is if someone else is making money off it, there is still money to be made. This kind of testing doesn't identify things like a red button converting better than a green button, but it can tell you if some users aren't seeing the button at all.