Do I need to skip days in between strength training?
 

So a few days ago I've started doing the following routine: leg lifts, crunches, leg raises, pushups, and planks. I do this on days when I can't get to the gym. Am I able to make this an everyday thing? I mean, is it safe/effective to do these exercises everyday save for the days I go to the gym?

I heard you should concentrate on different body parts on different days so you avoid overtraining. But I'm not a doctor. I do the same type of exercises you described above but I do them after my kettlebell routine on Tuesday and Thursday evenings only - so twice weekly. I've gotten good results thus far. Works for me.