no way thats true, especially for strength training. it takes about 2 weeks of not training to feel like a packet of jelly. at least if you're like me and sit on the computer most of the day
100%. Strength training is one of those things I've come to think of as body maintenance more than actually an athletic performance thing. Believe it to be equally if not more important than cardio
The best is to keep the momentum, making it part of your routine removes the willpower from the equation