I know some people do better with a routine, and I myself, am one of those people.
And my routine you should always have a plan. If you want to substitute routine for plan, that's fine. I hate the rigidity associated with most 'programs' for sale out there today. They sell a mysticism about some special effect they provide if they're adhered to completely and that's a bunch of bologna.
But at the other end of the spectrum, not having a plan/routine is a bad idea. Some consistency to build upon must always be in place in my opinion.
It changes from time to time based on my goals at the time. I'm currently training for improved athleticism and reducing body fat percentage. This plan consists of 2-3 days of strength training per week. Two of those days are heavy training days consisting of big exercises like squats, deadlifts, presses and rows. It usually consists of sets of 3-5 reps. The third day, which actually falls between these two days is a light day for training small stuff with higher volume like arms, abs, calves, etc. In most cases though this day is dropped since it's not needed.
Then there are also two days of circuit training per week geared at improving speed, agility, speed strength, strength endurance, and power/explosiveness.
These circuits consist of things like tire flips, sledge hammer slams, sand back work, jump rope, medicine ball work, speed ladder work, acceleration and deceleration work, calisthenics, etc, etc.
I also throw in a lot of prehab/rehab/corrective stuff in there to work out the kinks which consists of some dynamic mobility stuff, some static stretching and some myofascial release stuff.
All in all it usually come to about 4-5 hours of training per week and is working well.
Do you think you would become lazy if you got out of the groove of things?
Most likely not.
The 'groove' is not what keeps me focused. Rather my goals and aspirations are what I choose to focus on which keeps my momentum heading forward pretty consistently.
Does your routine impact staying " in shape" , your eating habits, exercise schedule?
My eating is geared toward my current goals and I do eat to facilitate my training and recovery.
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