Being stronger makes you a better person. You can help more friends move, spot more people, help carry some one out of a burning building... you get the picture.
I have tweaked my split several times, as any one should. At the end of last summer, I had my best 1RM bench PR (370lbs), yet I was noticing some pressure building in my shoulder on any press day. With that in mind I went to 1 chest and shoulder day (alternated emphasized movement), 1 leg day, and two back days for my four day split.
I assumed building some more back strength and stretching my chest and shoulder muscles more regularly would help balance the pull forward on my shoulders.
After five weeks of doing back twice a week, I took out a back day and added in a separate shoulder day with some more legs. I am pressure and pain free in my shoulder and am benching 10 more pounds than I was working out with last summer.
A couple people have asked me what my current split looks like. After some more tweaking, this is my NEW split that just started last Monday:
Monday: deadlift, back, and bicep
Tuesday: Olympic lifts focusing on explosion, sled pushes and pull, and later in the day Chest, tricep, and some straight arm shoulders
Thursday: Back and biceps- steady-state cardio
Friday: Shoulders, traps, triceps, and a fly movement + steady state cardio
I am always seeking improvement.