Re: Is it okay to do push-ups and sit-ups everyday?
No. Push-ups and sit-ups are just like using weights, except your body is the weight. It still stresses your muscles out, therefore they need time to recover. At best I would recommend every other day, but it depends on what other exercise you might do, and your recovery ability really. You could train 2 days on, 1 day off etc, but then I would allow a couple (more like 4 or 5) days break every few weeks to fully recover.