Is the "every other day" thing a good general rule, or is it just to build up your fitness gradually? My husband graduated the other week and struggles to fit runs in in term-time, being a teacher, because of all the work he has to do after school and helping with our 2 young kids. He usually only managed 1-2 runs a week unless it's the holidays. He reckons he might have better luck if he can be more flexible and go two days running if necessary (we currently run alternate days due to juggling childcare) but doesn't want to do this if it will cause him problems. Any advice?