I saved a fair bit before kids. Then me and my partner made the decision that we wanted one of us at home to bring up the kids, and not have them raised by daycare workers. So now we have one income, and more expenses than before. I'm reasonably well paid, drive older small cars, don't have any particularly expensive hobbies or holidays. I still save, and contribute to a private pension, but the idea of saving 50% of my income is unachievable.

Now that's fine if you don't want kids, but I often think these lifestyle philosophies promote themselves as fantastic and obvious, and why doesn't everyone do it. But forget to balance them with the hidden sacrifices you have to make that they never seem to mention.