A key question we must ask ourselves is to what extent we will support the use of particular browsers when developing our websites. The answer to this will lie in monitoring analytical software, to determine which browsers are being used.
In most cases, it should show modern browsers being used, but there are still limited instances of old browsers in use; for example, IE6 is still being used, although its market share is now a tiny 0.25%, as at April 2016. This raises the question of what we should support, if monitoring analytics for our sites shows that only a tiny percentage (that is, lower than 1%, for example) of usage is for older browsers, then we may take the decision to not support them if the effort and resources required do not justify the return from such a small market share.
This said, there are some basic tips that can help us optimize our sites:
We should avoid using hacks where possible. Conditional comments are a better option, although we should...