If you take your training seriously you need to understand the SAID principle: Specific Adaptation to Imposed Demands. This means that how you train has a direct impact on your results. You get out what you put in. The stimulus your provide creates the adaptation.
What that means to you: everything you do in the gym affect your training progress. Adaptation is specific. You won't increase your deadlift by doing biceps curls (although, you can actually train your biceps with the deadlift).
To understand SAID it is helpful to understand why it occurs...
Our bodies are constantly trying to be as efficient as possible in order to survive, which is why muscles will shrink and grow so quickly. If all that you do is sit on the couch and much potato chips, you don't need to have a big aerobic engine or be able to squat your body weight. On the other hand, when you exert yourself and keep pushing your limits the body responds by increasing your bone density, adding muscle mass and optimizing neural pathways. Neither adaption is "better", per say, but I can confidently say I would rather put on functional muscle than useless adipose tissue. It may sounds counter intuitive that our bodies would put on pounds of useless fat tissue, but in a pre-modern world fat was our friend (and still is) and we put as many calories in the bank as possible. When food is hard to come by we needed to indulge when we could, and store those calories for later use. In 21st century North America food is abundant and have more (much more) than we need. Our banks accounts are overflowing.
Muscle, unlike fat, is highly metabolic. It takes a lot of energy to operate. In other words, it is expensive. This is why muscles atrophy (i.e. shrink) so fast. If your body doesn't need to use the muscle it might as well get rid of it. This is still a Specific Adaptation, but the Imposed Demand is a sedentary lifestyle and hours of inactivity.
The problem with these adaptations are that they are short-term thinking. Your body isn't thinking "I shouldn't put on any more fat, because that can lead to heart disease and I might have a heart attack", instead it is thinking "YES. CALORIES. I CAN SURVIVE ANOTHER WEEK."
What that means to your performance: You can't undo 23 hrs by training 1 hr a day. If you want to improve your performance, you need to change your lifestyle. Your posture and daily habits are going to have a more significant and long-lasting impact than how many reps and sets you are doing.
What that means to your training: if you perform a conventional deadlift, you will get better at a conventional deadlift. Doing that is going to increase your leg power, and definitely make you stronger, faster, and more injury proof. BUT... (a big but), you are leaving performance on the table. You need to add variety to your training to experience other training adaptations. Deadlift sumo, conventional, romanian, from block, from deficit, at tempo, low reps, high reps.... variety if the king. That being said, there is no need to change your training session every day. Take time on each variety and gain strength there. Using other variations will help you maintain your strength (your brain still thinks you need it!)
At the end of the day, getting in the gym and putting in the work is the most important part of training. Your body adapts to the stimuli you provide it with. Make sure it is a positive one.
B.Kin, Canadian Society of Exercise Physiology CPT