If you've been following my training log for a while, you'll see that my training can be somewhat helter skelter. The ultimate goal would be to get 6 sessions in per week - 4 strength, 2 Krav Maga. Unfortunately, that doesn't always work out.
Instead, I'm a little bit more realistic about what can be done - I generally get in between four and five training sessions per week, which is more than enough to stay in shape and shed some body fat. The key here is that I have a fudge factor built in.
While I'd love to get in six sessions, I understand that it's not imperative for me to do so. In fact, I could probably continue to gain strength and shed body fat while only training three or four times per week. However, by planning for six sessions, I allow myself some freedom with regards to scheduling and such. Right now I'm working on several projects, including opening a gym, selling a home, and a host of other things. Quite simply, things come up and need to be addressed when I least expect it.
By allowing myself a little freedom with regards to my training schedule, I can continue to see progress. If I have to skip a session, I know it's not the end of the world because I've got something else planned later on to help make up for it.
What happens to most trainees is this: They have a schedule planned, and they're too rigid with it. Instead of understanding that things come up and interfere with their workouts, they compound the issue by thinking that they're "failling," and thus start a downward spiral. One missed workout turns into a bad meal later that night. That leads into another missed workout the next day, and you can see how things get out of control from there.
Remember that with all things there's "optimal" and then there's "real life." "Optimal" is great when/if you can make it happen. Unfortuantely for most of us, that's not all that often. Allow yourself a small fudge factor and you'll be happier with your training and the resulting success.