There's also a difference when you're developing your own site compared to when you're developing a framework or library. If your library is used on more than h

There's also a difference when you're developing your own site compared to when you're developing a framework or library. If your library is used on more than half of the top 100,000 websites (as jQuery is) then a 45KB saving or a 100ms speed boost, 50,000 times over is a big deal.