I also prefer to workout in the mornings. Even if that means waking up before 5am, but if I oversleep and miss my workout I try my hardest to do it in the evenings. You can google this and find different opinions on the matter. If you have a day with both cardio and weights, I've read that a split routine where you do your cardio in the mornings and weight training at night works great, most articles you'll find will say do cardio in the mornings, and weights in the evenings, but I think the best time to workout is whenever you feel like it. Also, there are several types of workouts you can do besides cardio or weights (yoga, ballet barre, pilates, etc.) so the time to do them is whenever you can fit them in your day. I am an expert when it comes to finding out excuses not to workout if I can't do it first thing in the morning, but I know I have to, even if I'm tired from work, I eat something with carbs about an hour before, and start my routine.