I've heard this a lot as a way to live life. I also read it in an article where the person who quoted it said if you aren't going to be better tomorrow than you are today, what's the point of tomorrow?
I don't view better from a skill set perspective or financial perspective. I do think there is a wonderful daily measure for how I'm doing: my relationships.
One way I seek spirit or God or whatever you want to call the higher energy is through relationships. Am I honest, patient and kind? Or do I "think" I'm honest, patient and kind.
I find that if I'm truly loving to you, I actually don't really sweat it if you see it differently. Now if dozens of people see it differently with me and I find myself with very few friends then perhaps there's something up!
Ultimately, it seems that in my relationships with you I reflect the way I feel about myself. And if I stay teachable and open I find that every day I'm growing. That's when I feel like I'm seeking God (rather than thinking I've found God, which is troubling).
It's nice to know there's not a destination. It's also nice to know that even though I'll be better tomorrow, I'm perfect today. That feels awesome.